//! Prototypes for various functions, mostly string utilities, that are used by most parts of fish. use crate::expand::{ BRACE_BEGIN, BRACE_END, BRACE_SEP, BRACE_SPACE, HOME_DIRECTORY, INTERNAL_SEPARATOR, PROCESS_EXPAND_SELF, PROCESS_EXPAND_SELF_STR, VARIABLE_EXPAND, VARIABLE_EXPAND_SINGLE, }; use crate::fallback::fish_wcwidth; use crate::future_feature_flags::{feature_test, FeatureFlag}; use crate::global_safety::AtomicRef; use crate::global_safety::RelaxedAtomicBool; use crate::key; use crate::libc::MB_CUR_MAX; use crate::parse_util::parse_util_escape_string_with_quote; use crate::termsize::Termsize; use crate::wchar::{decode_byte_from_char, encode_byte_to_char, prelude::*}; use crate::wcstringutil::wcs2string_callback; use crate::wildcard::{ANY_CHAR, ANY_STRING, ANY_STRING_RECURSIVE}; use crate::wutil::encoding::{mbrtowc, wcrtomb, zero_mbstate, AT_LEAST_MB_LEN_MAX}; use crate::wutil::fish_iswalnum; use bitflags::bitflags; use core::slice; use libc::{EIO, O_WRONLY, SIGTTOU, SIG_IGN, STDERR_FILENO, STDIN_FILENO, STDOUT_FILENO}; use once_cell::sync::OnceCell; use std::env; use std::ffi::{CStr, CString, OsStr, OsString}; use std::mem; use std::ops::{Deref, DerefMut}; use std::os::unix::prelude::*; use std::path::{Path, PathBuf}; use std::sync::atomic::{AtomicI32, AtomicU32, Ordering}; use std::sync::{Arc, MutexGuard}; use std::time; pub const PACKAGE_NAME: &str = env!("CARGO_PKG_NAME"); // Highest legal ASCII value. pub const ASCII_MAX: char = 127 as char; // Highest legal 16-bit Unicode value. pub const UCS2_MAX: char = '\u{FFFF}'; // Highest legal byte value. pub const BYTE_MAX: char = 0xFF as char; // Unicode BOM value. pub const UTF8_BOM_WCHAR: char = '\u{FEFF}'; // Use Unicode "non-characters" for internal characters as much as we can. This // gives us 32 "characters" for internal use that we can guarantee should not // appear in our input stream. See http://www.unicode.org/faq/private_use.html. pub const RESERVED_CHAR_BASE: char = '\u{FDD0}'; pub const RESERVED_CHAR_END: char = '\u{FDF0}'; // Split the available non-character values into two ranges to ensure there are // no conflicts among the places we use these special characters. pub const EXPAND_RESERVED_BASE: char = RESERVED_CHAR_BASE; pub const EXPAND_RESERVED_END: char = char_offset(EXPAND_RESERVED_BASE, 16); pub const WILDCARD_RESERVED_BASE: char = EXPAND_RESERVED_END; pub const WILDCARD_RESERVED_END: char = char_offset(WILDCARD_RESERVED_BASE, 16); // Make sure the ranges defined above don't exceed the range for non-characters. // This is to make sure we didn't do something stupid in subdividing the // Unicode range for our needs. const _: () = assert!(WILDCARD_RESERVED_END <= RESERVED_CHAR_END); // These are in the Unicode private-use range. We really shouldn't use this // range but have little choice in the matter given how our lexer/parser works. // We can't use non-characters for these two ranges because there are only 66 of // them and we need at least 256 + 64. // // If sizeof(wchar_t))==4 we could avoid using private-use chars; however, that // would result in fish having different behavior on machines with 16 versus 32 // bit wchar_t. It's better that fish behave the same on both types of systems. // // Note: We don't use the highest 8 bit range (0xF800 - 0xF8FF) because we know // of at least one use of a codepoint in that range: the Apple symbol (0xF8FF) // on Mac OS X. See http://www.unicode.org/faq/private_use.html. pub const ENCODE_DIRECT_BASE: char = '\u{F600}'; pub const ENCODE_DIRECT_END: char = char_offset(ENCODE_DIRECT_BASE, 256); #[derive(Debug, Clone, Copy, PartialEq, Eq)] pub enum EscapeStringStyle { Script(EscapeFlags), Url, Var, Regex, } impl Default for EscapeStringStyle { fn default() -> Self { Self::Script(EscapeFlags::default()) } } impl TryFrom<&wstr> for EscapeStringStyle { type Error = &'static wstr; fn try_from(s: &wstr) -> Result { use EscapeStringStyle::*; match s { s if s == "script" => Ok(Self::default()), s if s == "var" => Ok(Var), s if s == "url" => Ok(Url), s if s == "regex" => Ok(Regex), _ => Err(L!("Invalid escape style")), } } } bitflags! { /// Flags for the [`escape_string()`] function. These are only applicable when the escape style is /// [`EscapeStringStyle::Script`]. #[derive(Copy, Clone, Debug, Default, Eq, PartialEq)] pub struct EscapeFlags: u32 { /// Do not escape special fish syntax characters like the semicolon. Only escape non-printable /// characters and backslashes. const NO_PRINTABLES = 1 << 0; /// Do not try to use 'simplified' quoted escapes, and do not use empty quotes as the empty /// string. const NO_QUOTED = 1 << 1; /// Do not escape tildes. const NO_TILDE = 1 << 2; /// Replace non-printable control characters with Unicode symbols. const SYMBOLIC = 1 << 3; /// Escape : and = const SEPARATORS = 1 << 4; /// Escape , const COMMA = 1 << 5; } } #[derive(Debug, Clone, Copy, PartialEq, Eq)] pub enum UnescapeStringStyle { Script(UnescapeFlags), Url, Var, } impl Default for UnescapeStringStyle { fn default() -> Self { Self::Script(UnescapeFlags::default()) } } impl TryFrom<&wstr> for UnescapeStringStyle { type Error = &'static wstr; fn try_from(s: &wstr) -> Result { use UnescapeStringStyle::*; match s { s if s == "script" => Ok(Self::default()), s if s == "var" => Ok(Var), s if s == "url" => Ok(Url), _ => Err(L!("Invalid escape style")), } } } bitflags! { /// Flags for unescape_string functions. #[derive(Copy, Clone, Debug, Default, Eq, PartialEq)] pub struct UnescapeFlags: u32 { /// escape special fish syntax characters like the semicolon const SPECIAL = 1 << 0; /// allow incomplete escape sequences const INCOMPLETE = 1 << 1; /// don't handle backslash escapes const NO_BACKSLASHES = 1 << 2; } } /// Replace special characters with backslash escape sequences. Newline is replaced with `\n`, etc. pub fn escape(s: &wstr) -> WString { escape_string(s, EscapeStringStyle::Script(EscapeFlags::default())) } /// Replace special characters with backslash escape sequences. Newline is replaced with `\n`, etc. pub fn escape_string(s: &wstr, style: EscapeStringStyle) -> WString { match style { EscapeStringStyle::Script(flags) => escape_string_script(s, flags), EscapeStringStyle::Url => escape_string_url(s), EscapeStringStyle::Var => escape_string_var(s), EscapeStringStyle::Regex => escape_string_pcre2(s), } } /// Escape a string in a fashion suitable for using in fish script. fn escape_string_script(input: &wstr, flags: EscapeFlags) -> WString { let escape_printables = !flags.contains(EscapeFlags::NO_PRINTABLES); let escape_separators = flags.contains(EscapeFlags::SEPARATORS); let escape_comma = flags.contains(EscapeFlags::COMMA); let no_quoted = flags.contains(EscapeFlags::NO_QUOTED); let no_tilde = flags.contains(EscapeFlags::NO_TILDE); let no_qmark = feature_test(FeatureFlag::qmark_noglob); let symbolic = flags.contains(EscapeFlags::SYMBOLIC) && MB_CUR_MAX() > 1; assert!( !symbolic || !escape_printables, "symbolic implies escape-no-printables" ); let mut need_escape = false; let mut need_complex_escape = false; let mut double_quotes = 0; let mut single_quotes = 0; let mut dollars = 0; if !no_quoted && input.is_empty() { return L!("''").to_owned(); } let mut out = WString::new(); for c in input.chars() { if let Some(val) = decode_byte_from_char(c) { out += "\\X"; let nibble1 = val / 16; let nibble2 = val % 16; out.push(char::from_digit(nibble1.into(), 16).unwrap()); out.push(char::from_digit(nibble2.into(), 16).unwrap()); need_escape = true; need_complex_escape = true; continue; } match c { '\t' => { if symbolic { out.push('␉'); } else { out += L!("\\t"); } need_escape = true; need_complex_escape = true; } '\n' => { if symbolic { out.push('␤'); } else { out += L!("\\n"); } need_escape = true; need_complex_escape = true; } '\x08' => { if symbolic { out.push('␈'); } else { out += L!("\\b"); } need_escape = true; need_complex_escape = true; } '\r' => { if symbolic { out.push('␍'); } else { out += L!("\\r"); } need_escape = true; need_complex_escape = true; } '\x1B' => { if symbolic { out.push('␛'); } else { out += L!("\\e"); } need_escape = true; need_complex_escape = true; } '\x7F' => { if symbolic { out.push('␡'); } else { out += L!("\\x7f"); } need_escape = true; need_complex_escape = true; } '\\' | '\'' => { need_escape = true; if c == '\'' { single_quotes += 1; } if escape_printables || (c == '\\' && !symbolic) { out.push('\\'); } out.push(c); } ANY_CHAR => { // See #1614 out.push('?'); } ANY_STRING => { out.push('*'); } ANY_STRING_RECURSIVE => { out += L!("**"); } ':' | '=' => { if escape_separators { need_escape = true; out.push('\\'); } out.push(c); } ',' => { if escape_comma { need_escape = true; out.push('\\'); } out.push(c); } '&' | '$' | ' ' | '#' | '<' | '>' | '(' | ')' | '[' | ']' | '{' | '}' | '?' | '*' | '|' | ';' | '"' | '%' | '~' => { if c == '"' { double_quotes += 1; } if c == '$' { dollars += 1; } let char_is_normal = (c == '~' && no_tilde) || (c == '?' && no_qmark); if !char_is_normal { need_escape = true; if escape_printables { out.push('\\') }; } out.push(c); } '\x00'..='\x19' => { let cval = u32::from(c); need_escape = true; need_complex_escape = true; if symbolic { out.push(char::from_u32(0x2400 + cval).unwrap()); continue; } if cval < 27 && cval != 0 { out.push('\\'); out.push('c'); out.push(char::from_u32(u32::from(b'a') + cval - 1).unwrap()); continue; } let nibble = cval % 16; out.push('\\'); out.push('x'); out.push(if cval > 15 { '1' } else { '0' }); out.push(char::from_digit(nibble, 16).unwrap()); } _ => out.push(c), } } // Use quoted escaping if possible, since most people find it easier to read. if !no_quoted && need_escape && !need_complex_escape && escape_printables { let quote = if single_quotes > double_quotes + dollars { '"' } else { '\'' }; out.clear(); out.reserve(2 + input.len()); out.push(quote); out.push_utfstr(&parse_util_escape_string_with_quote( input, Some(quote), EscapeFlags::empty(), )); out.push(quote); } out } /// Test whether the char is a valid hex digit as used by the `escape_string_*()` functions. /// Note this only considers uppercase characters. fn is_upper_hex_digit(c: char) -> bool { matches!(c, '0'..='9' | 'A'..='F') } /// Return the high and low nibbles of a byte, as uppercase hex characters. fn byte_to_hex(byte: u8) -> (char, char) { const HEX: [u8; 16] = *b"0123456789ABCDEF"; let high = byte >> 4; let low = byte & 0xF; (HEX[high as usize].into(), HEX[low as usize].into()) } /// Escape a string in a fashion suitable for using as a URL. Store the result in out_str. fn escape_string_url(input: &wstr) -> WString { let narrow = wcs2string(input); let mut out = WString::new(); for byte in narrow.into_iter() { if (byte & 0x80) == 0 { let c = char::from_u32(u32::from(byte)).unwrap(); if c.is_alphanumeric() || [b'/', b'.', b'~', b'-', b'_'].contains(&byte) { // The above characters don't need to be encoded. out.push(c); continue; } } // All other chars need to have their narrow representation encoded in hex. let (high, low) = byte_to_hex(byte); out.push('%'); out.push(high); out.push(low); } out } /// Escape a string in a fashion suitable for using as a fish var name. Store the result in out_str. fn escape_string_var(input: &wstr) -> WString { let mut prev_was_hex_encoded = false; let narrow = wcs2string(input); let mut out = WString::new(); for c in narrow.into_iter() { let ch: char = c.into(); if ((c & 0x80) == 0 && ch.is_alphanumeric()) && (!prev_was_hex_encoded || !is_upper_hex_digit(ch)) { // ASCII alphanumerics don't need to be encoded. if prev_was_hex_encoded { out.push('_'); prev_was_hex_encoded = false; } out.push(ch); } else if c == b'_' { // Underscores are encoded by doubling them. out.push_str("__"); prev_was_hex_encoded = false; } else { // All other chars need to have their narrow representation encoded in hex. let (high, low) = byte_to_hex(c); out.push('_'); out.push(high); out.push(low); prev_was_hex_encoded = true; } } if prev_was_hex_encoded { out.push('_'); } out } /// Escapes a string for use in a regex string. Not safe for use with `eval` as only /// characters reserved by PCRE2 are escaped. /// \param in is the raw string to be searched for literally when substituted in a PCRE2 expression. fn escape_string_pcre2(input: &wstr) -> WString { let mut out = WString::new(); out.reserve(input.len() + input.len() / 2); for c in input.chars() { if c == '\n' { out.push_str("\\n"); continue; } if [ '.', '^', '$', '*', '+', '(', ')', '?', '[', '{', '}', '\\', '|', // these two only *need* to be escaped within a character class, and technically it // makes no sense to ever use process substitution output to compose a character class, // but... '-', ']', ] .contains(&c) { out.push('\\'); } out.push(c); } out } /// Escape a string so that it may be inserted into a double-quoted string. /// This permits ownership transfer. pub fn escape_string_for_double_quotes(input: &wstr) -> WString { // We need to escape backslashes, double quotes, and dollars only. let mut result = input.to_owned(); let mut idx = result.len(); while idx > 0 { idx -= 1; if ['\\', '$', '"'].contains(&result.char_at(idx)) { result.insert(idx, '\\'); } } result } pub fn unescape_string(input: &wstr, style: UnescapeStringStyle) -> Option { match style { UnescapeStringStyle::Script(flags) => unescape_string_internal(input, flags), UnescapeStringStyle::Url => unescape_string_url(input), UnescapeStringStyle::Var => unescape_string_var(input), } } /// Returns the unescaped version of input, or None on error. fn unescape_string_internal(input: &wstr, flags: UnescapeFlags) -> Option { let mut result = WString::new(); result.reserve(input.len()); let unescape_special = flags.contains(UnescapeFlags::SPECIAL); let allow_incomplete = flags.contains(UnescapeFlags::INCOMPLETE); let ignore_backslashes = flags.contains(UnescapeFlags::NO_BACKSLASHES); let allow_percent_self = !feature_test(FeatureFlag::remove_percent_self); // The positions of open braces. let mut braces = vec![]; // The positions of variable expansions or brace ","s. // We only read braces as expanders if there's a variable expansion or "," in them. let mut vars_or_seps = vec![]; let mut brace_count = 0; let mut potential_word_start = None; let mut errored = false; #[derive(PartialEq, Eq)] enum Mode { Unquoted, SingleQuotes, DoubleQuotes, } let mut mode = Mode::Unquoted; let mut input_position = 0; while input_position < input.len() && !errored { let c = input.char_at(input_position); // Here's the character we'll append to result, or none() to suppress it. let mut to_append_or_none = Some(c); if mode == Mode::Unquoted { match c { '\\' => { if !ignore_backslashes { // Backslashes (escapes) are complicated and may result in errors, or // appending INTERNAL_SEPARATORs, so we have to handle them specially. if let Some(escape_chars) = read_unquoted_escape( &input[input_position..], &mut result, allow_incomplete, unescape_special, ) { // Skip over the characters we read, minus one because the outer loop // will increment it. assert!(escape_chars > 0); input_position += escape_chars - 1; } else { // A none() return indicates an error. errored = true; } // We've already appended, don't append anything else. to_append_or_none = None; } } '~' => { if unescape_special && (input_position == 0 || Some(input_position) == potential_word_start) { to_append_or_none = Some(HOME_DIRECTORY); } } '%' => { // Note that this only recognizes %self if the string is literally %self. // %self/foo will NOT match this. if allow_percent_self && unescape_special && input_position == 0 && input == PROCESS_EXPAND_SELF_STR { to_append_or_none = Some(PROCESS_EXPAND_SELF); input_position += PROCESS_EXPAND_SELF_STR.len() - 1; // skip over 'self's } } '*' => { if unescape_special { // In general, this is ANY_STRING. But as a hack, if the last appended char // is ANY_STRING, delete the last char and store ANY_STRING_RECURSIVE to // reflect the fact that ** is the recursive wildcard. if result.chars().next_back() == Some(ANY_STRING) { assert!(!result.is_empty()); result.truncate(result.len() - 1); to_append_or_none = Some(ANY_STRING_RECURSIVE); } else { to_append_or_none = Some(ANY_STRING); } } } '?' => { if unescape_special && !feature_test(FeatureFlag::qmark_noglob) { to_append_or_none = Some(ANY_CHAR); } } '$' => { if unescape_special { let is_cmdsub = input_position + 1 < input.len() && input.char_at(input_position + 1) == '('; if !is_cmdsub { to_append_or_none = Some(VARIABLE_EXPAND); vars_or_seps.push(input_position); } } } '{' => { if unescape_special { brace_count += 1; to_append_or_none = Some(BRACE_BEGIN); // We need to store where the brace *ends up* in the output. braces.push(result.len()); potential_word_start = Some(input_position + 1); } } '}' => { if unescape_special { // HACK: The completion machinery sometimes hands us partial tokens. // We can't parse them properly, but it shouldn't hurt, // so we don't assert here. // See #4954. // assert(brace_count > 0 && "imbalanced brackets are a tokenizer error, we // shouldn't be able to get here"); brace_count -= 1; to_append_or_none = Some(BRACE_END); if let Some(brace) = braces.pop() { // HACK: To reduce accidental use of brace expansion, treat a brace // with zero or one items as literal input. See #4632. (The hack is // doing it here and like this.) if vars_or_seps.last().map(|i| *i < brace).unwrap_or(true) { result.as_char_slice_mut()[brace] = '{'; // We also need to turn all spaces back. for i in brace + 1..result.len() { if result.char_at(i) == BRACE_SPACE { result.as_char_slice_mut()[i] = ' '; } } to_append_or_none = Some('}'); } // Remove all seps inside the current brace pair, so if we have a // surrounding pair we only get seps inside *that*. if !vars_or_seps.is_empty() { while vars_or_seps.last().map(|i| *i > brace).unwrap_or_default() { vars_or_seps.pop(); } } } } } ',' => { if unescape_special && brace_count > 0 { to_append_or_none = Some(BRACE_SEP); vars_or_seps.push(input_position); potential_word_start = Some(input_position + 1); } } ' ' => { if unescape_special && brace_count > 0 { to_append_or_none = Some(BRACE_SPACE); } } '\'' => { mode = Mode::SingleQuotes; to_append_or_none = if unescape_special { Some(INTERNAL_SEPARATOR) } else { None }; } '"' => { mode = Mode::DoubleQuotes; to_append_or_none = if unescape_special { Some(INTERNAL_SEPARATOR) } else { None }; } _ => (), } } else if mode == Mode::SingleQuotes { if c == '\\' { // A backslash may or may not escape something in single quotes. match input.char_at(input_position + 1) { '\\' | '\'' => { to_append_or_none = Some(input.char_at(input_position + 1)); input_position += 1; // skip over the backslash } '\0' => { if !allow_incomplete { errored = true; } else { // PCA this line had the following cryptic comment: 'We may ever escape // a NULL character, but still appending a \ in case I am wrong.' Not // sure what it means or the importance of this. input_position += 1; /* Skip over the backslash */ to_append_or_none = Some('\\'); } } _ => { // Literal backslash that doesn't escape anything! Leave things alone; we'll // append the backslash itself. } } } else if c == '\'' { to_append_or_none = if unescape_special { Some(INTERNAL_SEPARATOR) } else { None }; mode = Mode::Unquoted; } } else if mode == Mode::DoubleQuotes { match c { '"' => { mode = Mode::Unquoted; to_append_or_none = if unescape_special { Some(INTERNAL_SEPARATOR) } else { None }; } '\\' => { match input.char_at(input_position + 1) { '\0' => { if !allow_incomplete { errored = true; } else { to_append_or_none = Some('\0'); } } '\\' | '$' | '"' => { to_append_or_none = Some(input.char_at(input_position + 1)); input_position += 1; /* Skip over the backslash */ } '\n' => { /* Swallow newline */ to_append_or_none = None; input_position += 1; /* Skip over the backslash */ } _ => { /* Literal backslash that doesn't escape anything! Leave things alone; * we'll append the backslash itself */ } } } '$' => { if unescape_special { to_append_or_none = Some(VARIABLE_EXPAND_SINGLE); vars_or_seps.push(input_position); } } _ => (), } } // Now maybe append the char. if let Some(c) = to_append_or_none { result.push(c); } input_position += 1; } // Return the string by reference, and then success. if errored { return None; } Some(result) } /// Reverse the effects of `escape_string_url()`. By definition the input should consist of just /// ASCII chars. fn unescape_string_url(input: &wstr) -> Option { let mut result: Vec = Vec::with_capacity(input.len()); let mut i = 0; while i < input.len() { let c = input.char_at(i); if c > '\u{7F}' { return None; // invalid character means we can't decode the string } if c == '%' { let c1 = input.char_at(i + 1); if c1 == '\0' { return None; } else if c1 == '%' { result.push(b'%'); i += 1; } else { let d1 = c1.to_digit(16)?; let c2 = input.char_at(i + 2); let d2 = c2.to_digit(16)?; // also fails if '\0' i.e. premature end result.push((16 * d1 + d2) as u8); i += 2; } } else { result.push(c as u8); } i += 1 } Some(str2wcstring(&result)) } /// Reverse the effects of `escape_string_var()`. By definition the string should consist of just /// ASCII chars. fn unescape_string_var(input: &wstr) -> Option { let mut result: Vec = Vec::with_capacity(input.len()); let mut prev_was_hex_encoded = false; let mut i = 0; while i < input.len() { let c = input.char_at(i); if c > '\u{7F}' { return None; // invalid character means we can't decode the string } if c == '_' { let c1 = input.char_at(i + 1); if c1 == '\0' { if prev_was_hex_encoded { break; } return None; // found unexpected escape char at end of string } else if c1 == '_' { result.push(b'_'); i += 1; } else if is_upper_hex_digit(c1) { let d1 = c1.to_digit(16)?; let c2 = input.char_at(i + 2); let d2 = c2.to_digit(16)?; // also fails if '\0' i.e. premature end result.push((16 * d1 + d2) as u8); i += 2; prev_was_hex_encoded = true; } // No "else" clause because if the first char after an underscore is not another // underscore or a valid hex character then the underscore is there to improve // readability after we've encoded a character not valid in a var name. } else { result.push(c as u8); } i += 1; } Some(str2wcstring(&result)) } /// Given a string starting with a backslash, read the escape as if it is unquoted, appending /// to result. Return the number of characters consumed, or none on error. pub fn read_unquoted_escape( input: &wstr, result: &mut WString, allow_incomplete: bool, unescape_special: bool, ) -> Option { assert!(input.char_at(0) == '\\', "not an escape"); // Here's the character we'll ultimately append, or none. Note that '\0' is a // valid thing to append. let mut result_char_or_none: Option = None; let mut errored = false; let mut in_pos = 1; // in_pos always tracks the next character to read (and therefore the number // of characters read so far) // For multibyte \X sequences. let mut byte_buff: Vec = vec![]; loop { let c = input.char_at(in_pos); in_pos += 1; match c { // A null character after a backslash is an error. '\0' => { // Adjust in_pos to only include the backslash. assert!(in_pos > 0); in_pos -= 1; // It's an error, unless we're allowing incomplete escapes. if !allow_incomplete { errored = true; } } // Numeric escape sequences. No prefix means octal escape, otherwise hexadecimal. '0'..='7' | 'u' | 'U' | 'x' | 'X' => { let mut res: u64 = 0; let mut chars = 2; let mut base = 16; let mut byte_literal = false; let mut max_val = ASCII_MAX; match c { 'u' => { chars = 4; max_val = UCS2_MAX; } 'U' => { chars = 8; // Don't exceed the largest Unicode code point - see #1107. max_val = char::MAX; } 'x' | 'X' => { byte_literal = true; max_val = BYTE_MAX; } _ => { base = 8; chars = 3; // Note that in_pos currently is just after the first post-backslash // character; we want to start our escape from there. assert!(in_pos > 0); in_pos -= 1; } } for i in 0..chars { let Some(d) = input.char_at(in_pos).to_digit(base) else { // If we have no digit, this is a tokenizer error. if i == 0 { errored = true; } break; }; res = (res * u64::from(base)) + u64::from(d); in_pos += 1; } if !errored && res <= u64::from(max_val) { if byte_literal { // Multibyte encodings necessitate that we keep adjacent byte escapes. // - `\Xc3\Xb6` is "ö", but only together. // (this assumes a valid codepoint can't consist of multiple bytes // that are valid on their own, which is true for UTF-8) byte_buff.push(res.try_into().unwrap()); result_char_or_none = None; if input[in_pos..].starts_with("\\X") || input[in_pos..].starts_with("\\x") { in_pos += 1; continue; } } else { result_char_or_none = Some(char::from_u32(res.try_into().unwrap()).unwrap_or('\u{FFFD}')); } } else { errored = true; } } // \a means bell (alert). 'a' => { result_char_or_none = Some('\x07'); } // \b means backspace. 'b' => { result_char_or_none = Some('\x08'); } // \cX means control sequence X. 'c' => { let sequence_char = u32::from(input.char_at(in_pos)); in_pos += 1; if sequence_char >= u32::from('a') && sequence_char <= u32::from('a') + 32 { result_char_or_none = Some(char::from_u32(sequence_char - u32::from('a') + 1).unwrap()); } else if sequence_char >= u32::from('A') && sequence_char <= u32::from('A') + 32 { result_char_or_none = Some(char::from_u32(sequence_char - u32::from('A') + 1).unwrap()); } else { errored = true; } } // \x1B means escape. 'e' => { result_char_or_none = Some('\x1B'); } // \f means form feed. 'f' => { result_char_or_none = Some('\x0C'); } // \n means newline. 'n' => { result_char_or_none = Some('\n'); } // \r means carriage return. 'r' => { result_char_or_none = Some('\x0D'); } // \t means tab. 't' => { result_char_or_none = Some('\t'); } // \v means vertical tab. 'v' => { result_char_or_none = Some('\x0b'); } // If a backslash is followed by an actual newline, swallow them both. '\n' => { result_char_or_none = None; } _ => { if unescape_special { result.push(INTERNAL_SEPARATOR); } result_char_or_none = Some(c); } } if errored { return None; } if !byte_buff.is_empty() { result.push_utfstr(&str2wcstring(&byte_buff)); } break; } if let Some(c) = result_char_or_none { if fish_reserved_codepoint(c) { return None; } result.push(c); } Some(in_pos) } pub const fn char_offset(base: char, offset: u32) -> char { match char::from_u32(base as u32 + offset) { Some(c) => c, None => panic!("not a valid char"), } } /// Exits without invoking destructors (via _exit), useful for code after fork. pub fn exit_without_destructors(code: libc::c_int) -> ! { unsafe { libc::_exit(code) }; } pub fn shell_modes() -> MutexGuard<'static, libc::termios> { crate::reader::SHELL_MODES.lock().unwrap() } /// The character to use where the text has been truncated. Is an ellipsis on unicode system and a $ /// on other systems. pub fn get_ellipsis_char() -> char { char::from_u32(ELLIPSIS_CHAR.load(Ordering::Relaxed)).unwrap() } static ELLIPSIS_CHAR: AtomicU32 = AtomicU32::new(0); /// The character or string to use where text has been truncated (ellipsis if possible, otherwise /// ...) pub fn get_ellipsis_str() -> &'static wstr { ELLIPSIS_STRING.load() } static ELLIPSIS_STRING: AtomicRef = AtomicRef::new(&L!("")); /// Character representing an omitted newline at the end of text. pub fn get_omitted_newline_str() -> &'static wstr { OMITTED_NEWLINE_STR.load() } static OMITTED_NEWLINE_STR: AtomicRef = AtomicRef::new(&L!("")); pub fn get_omitted_newline_width() -> usize { OMITTED_NEWLINE_STR.load().len() } static OBFUSCATION_READ_CHAR: AtomicU32 = AtomicU32::new(0); pub fn get_obfuscation_read_char() -> char { char::from_u32(OBFUSCATION_READ_CHAR.load(Ordering::Relaxed)).unwrap() } /// Profiling flag. True if commands should be profiled. pub static PROFILING_ACTIVE: RelaxedAtomicBool = RelaxedAtomicBool::new(false); /// Name of the current program. Should be set at startup. Used by the debug function. pub static PROGRAM_NAME: OnceCell<&'static wstr> = OnceCell::new(); /// MS Windows tty devices do not currently have either a read or write timestamp - those respective /// fields of `struct stat` are always set to the current time, which means we can't rely on them. /// In this case, we assume no external program has written to the terminal behind our back, making /// the multiline prompt usable. See #2859 and https://github.com/Microsoft/BashOnWindows/issues/545 pub fn has_working_tty_timestamps() -> bool { if cfg!(target_os = "windows") { false } else if cfg!(target_os = "linux") { !is_windows_subsystem_for_linux(WSL::V1) } else { true } } /// A global, empty string. This is useful for functions which wish to return a reference to an /// empty string. pub static EMPTY_STRING: WString = WString::new(); /// A function type to check for cancellation. /// Return true if execution should cancel. /// todo!("Maybe remove the box? It is only needed for get_bg_context.") pub type CancelChecker = Box bool>; /// Converts the narrow character string \c in into its wide equivalent, and return it. /// /// The string may contain embedded nulls. /// /// This function encodes illegal character sequences in a reversible way using the private use /// area. pub fn str2wcstring(inp: &[u8]) -> WString { if inp.is_empty() { return WString::new(); } let mut result = WString::new(); result.reserve(inp.len()); let mut pos = 0; let mut state = zero_mbstate(); while pos < inp.len() { // Append any initial sequence of ascii characters. // Note we do not support character sets which are not supersets of ASCII. let ascii_prefix_length = count_ascii_prefix(&inp[pos..]); result.push_str(std::str::from_utf8(&inp[pos..pos + ascii_prefix_length]).unwrap()); pos += ascii_prefix_length; assert!(pos <= inp.len(), "Position overflowed length"); if pos == inp.len() { break; } // We have found a non-ASCII character. let mut ret = 0; let mut c = '\0'; let use_encode_direct = if inp[pos] & 0xF8 == 0xF8 { // Protect against broken mbrtowc() implementations which attempt to encode UTF-8 // sequences longer than four bytes (e.g., OS X Snow Leopard). // TODO This check used to be conditionally compiled only on affected platforms. true } else { const _: () = assert!(mem::size_of::() == mem::size_of::()); let mut codepoint = u32::from(c); ret = unsafe { mbrtowc( std::ptr::addr_of_mut!(codepoint).cast(), std::ptr::addr_of!(inp[pos]).cast(), inp.len() - pos, &mut state, ) }; match char::from_u32(codepoint) { Some(codepoint) => { c = codepoint; // Determine whether to encode this character with our crazy scheme. fish_reserved_codepoint(c) || // Incomplete sequence. ret == 0_usize.wrapping_sub(2) || // Invalid data. ret == 0_usize.wrapping_sub(1) || // Other error codes? Terrifying, should never happen. ret > inp.len() - pos } None => true, } }; if use_encode_direct { c = encode_byte_to_char(inp[pos]); result.push(c); pos += 1; state = zero_mbstate(); } else if ret == 0 { // embedded null byte! result.push('\0'); pos += 1; state = zero_mbstate(); } else { // normal case result.push(c); pos += ret; } } result } /// Given an input string, return a prefix of the string up to the first NUL character, /// or the entire string if there is no NUL character. pub fn truncate_at_nul(input: &wstr) -> &wstr { match input.chars().position(|c| c == '\0') { Some(nul_pos) => &input[..nul_pos], None => input, } } pub fn cstr2wcstring(input: &[u8]) -> WString { let strlen = input.iter().position(|c| *c == b'\0').unwrap(); str2wcstring(&input[0..strlen]) } pub(crate) fn charptr2wcstring(input: *const libc::c_char) -> WString { let input: &[u8] = unsafe { let strlen = libc::strlen(input); slice::from_raw_parts(input.cast(), strlen) }; str2wcstring(input) } /// Returns a newly allocated multibyte character string equivalent of the specified wide character /// string. /// /// This function decodes illegal character sequences in a reversible way using the private use /// area. pub fn wcs2string(input: &wstr) -> Vec { if input.is_empty() { return vec![]; } let mut result = vec![]; wcs2string_appending(&mut result, input); result } pub fn wcs2osstring(input: &wstr) -> OsString { if input.is_empty() { return OsString::new(); } let mut result = vec![]; wcs2string_appending(&mut result, input); OsString::from_vec(result) } /// Same as [`wcs2string`]. Meant to be used when we need a zero-terminated string to feed legacy APIs. /// Note: if `input` contains any interior NUL bytes, the result will be truncated at the first! pub fn wcs2zstring(input: &wstr) -> CString { if input.is_empty() { return CString::default(); } let mut vec = Vec::with_capacity(input.len() + 1); wcs2string_callback(input, |buff| { vec.extend_from_slice(buff); true }); vec.push(b'\0'); match CString::from_vec_with_nul(vec) { Ok(cstr) => cstr, Err(err) => { // `input` contained a NUL in the middle; we can retrieve `vec`, though let mut vec = err.into_bytes(); let pos = vec.iter().position(|c| *c == b'\0').unwrap(); vec.truncate(pos + 1); // Safety: We truncated after the first NUL unsafe { CString::from_vec_with_nul_unchecked(vec) } } } } /// Like wcs2string, but appends to `receiver` instead of returning a new string. pub fn wcs2string_appending(output: &mut Vec, input: &wstr) { output.reserve(input.len()); wcs2string_callback(input, |buff| { output.extend_from_slice(buff); true }); } /// Return the count of initial characters in `in` which are ASCII. fn count_ascii_prefix(inp: &[u8]) -> usize { // The C++ version had manual vectorization. inp.iter().take_while(|c| c.is_ascii()).count() } // Check if we are running in the test mode, where we should suppress error output pub const TESTS_PROGRAM_NAME: &wstr = L!("(ignore)"); /// Hack to not print error messages in the tests. Do not call this from functions in this module /// like `debug()`. It is only intended to suppress diagnostic noise from testing things like the /// fish parser where we expect a lot of diagnostic messages due to testing error conditions. pub fn should_suppress_stderr_for_tests() -> bool { PROGRAM_NAME .get() .map(|p| p == TESTS_PROGRAM_NAME) .unwrap_or_default() } /// Stored in blocks to reference the file which created the block. pub type FilenameRef = Arc; /// This function should be called after calling `setlocale()` to perform fish specific locale /// initialization. pub fn fish_setlocale() { // Helper to make a static reference to a static &'wstr, from a string literal. // This is necessary to store them in global atomics, as these can't handle fat pointers. macro_rules! LL { ($s:literal) => {{ const S: &'static wstr = L!($s); &S }}; } // Use various Unicode symbols if they can be encoded using the current locale, else a simple // ASCII char alternative. All of the can_be_encoded() invocations should return the same // true/false value since the code points are in the BMP but we're going to be paranoid. This // is also technically wrong if we're not in a Unicode locale but we expect (or hope) // can_be_encoded() will return false in that case. if can_be_encoded('\u{2026}') { ELLIPSIS_CHAR.store(u32::from('\u{2026}'), Ordering::Relaxed); ELLIPSIS_STRING.store(LL!("\u{2026}")); } else { ELLIPSIS_CHAR.store(u32::from('$'), Ordering::Relaxed); // "horizontal ellipsis" ELLIPSIS_STRING.store(LL!("...")); } if is_windows_subsystem_for_linux(WSL::Any) { // neither of \u23CE and \u25CF can be displayed in the default fonts on Windows, though // they can be *encoded* just fine. Use alternative glyphs. OMITTED_NEWLINE_STR.store(LL!("\u{00b6}")); // "pilcrow" OBFUSCATION_READ_CHAR.store(u32::from('\u{2022}'), Ordering::Relaxed); // "bullet" } else if is_console_session() { OMITTED_NEWLINE_STR.store(LL!("^J")); OBFUSCATION_READ_CHAR.store(u32::from('*'), Ordering::Relaxed); } else { if can_be_encoded('\u{23CE}') { OMITTED_NEWLINE_STR.store(LL!("\u{23CE}")); // "return symbol" (⏎) } else { OMITTED_NEWLINE_STR.store(LL!("^J")); } OBFUSCATION_READ_CHAR.store( u32::from(if can_be_encoded('\u{25CF}') { '\u{25CF}' // "black circle" } else { '#' }), Ordering::Relaxed, ); } } /// Test if the character can be encoded using the current locale. fn can_be_encoded(wc: char) -> bool { let mut converted = [0 as libc::c_char; AT_LEAST_MB_LEN_MAX]; let mut state = zero_mbstate(); unsafe { wcrtomb(converted.as_mut_ptr(), wc as libc::wchar_t, &mut state) != 0_usize.wrapping_sub(1) } } /// Call read, blocking and repeating on EINTR. Exits on EAGAIN. /// Return the number of bytes read, or 0 on EOF, or an error. pub fn read_blocked(fd: RawFd, buf: &mut [u8]) -> nix::Result { loop { let res = nix::unistd::read(fd, buf); if let Err(nix::Error::EINTR) = res { continue; } return res; } } /// Test if the string is a valid function name. pub fn valid_func_name(name: &wstr) -> bool { !(name.is_empty() || name.starts_with('-') // A function name needs to be a valid path, so no / and no NULL. || name.contains('/') || name.contains('\0')) } /// A rusty port of the C++ `write_loop()` function from `common.cpp`. This should be deprecated in /// favor of native rust read/write methods at some point. /// /// Returns the number of bytes written or an IO error. pub fn write_loop(fd: &Fd, buf: &[u8]) -> std::io::Result { let fd = fd.as_raw_fd(); let mut total = 0; while total < buf.len() { match nix::unistd::write(unsafe { BorrowedFd::borrow_raw(fd) }, &buf[total..]) { Ok(written) => { total += written; } Err(err) => { if matches!(err, nix::Error::EAGAIN | nix::Error::EINTR) { continue; } return Err(std::io::Error::from(err)); } } } Ok(total) } /// A rusty port of the C++ `read_loop()` function from `common.cpp`. This should be deprecated in /// favor of native rust read/write methods at some point. /// /// Returns the number of bytes read or an IO error. pub fn read_loop(fd: &Fd, buf: &mut [u8]) -> std::io::Result { let fd = fd.as_raw_fd(); loop { match nix::unistd::read(fd, buf) { Ok(read) => { return Ok(read); } Err(err) => { if matches!(err, nix::Error::EAGAIN | nix::Error::EINTR) { continue; } return Err(std::io::Error::from(err)); } } } } /// Write the given paragraph of output, redoing linebreaks to fit `termsize`. pub fn reformat_for_screen(msg: &wstr, termsize: &Termsize) -> WString { let mut buff = WString::new(); let screen_width = termsize.width; if screen_width != 0 { let mut start = 0; let mut pos = start; let mut line_width = 0; while pos < msg.len() { let mut overflow = false; let mut tok_width = 0; // Tokenize on whitespace, and also calculate the width of the token. while pos < msg.len() && ![' ', '\n', '\r', '\t'].contains(&msg.char_at(pos)) { // Check is token is wider than one line. If so we mark it as an overflow and break // the token. let width = fish_wcwidth(msg.char_at(pos)); if (tok_width + width) > (screen_width - 1) { overflow = true; break; } tok_width += width; pos += 1; } // If token is zero character long, we don't do anything. if pos == start { pos += 1; } else if overflow { // In case of overflow, we print a newline, except if we already are at position 0. let token = &msg[start..pos]; if line_width != 0 { buff.push('\n'); } buff += &sprintf!("%ls-\n", token)[..]; line_width = 0; } else { // Print the token. let token = &msg[start..pos]; let line_width_unit = if line_width != 0 { 1 } else { 0 }; if (line_width + line_width_unit + tok_width) > screen_width { buff.push('\n'); line_width = 0; } if line_width != 0 { buff += L!(" "); } buff += token; line_width += line_width_unit + tok_width; } start = pos; } } else { buff += msg; } buff.push('\n'); buff } pub type Timepoint = f64; /// Return the number of seconds from the UNIX epoch, with subsecond precision. This function uses /// the gettimeofday function and will have the same precision as that function. pub fn timef() -> Timepoint { match time::SystemTime::now().duration_since(time::UNIX_EPOCH) { Ok(difference) => difference.as_secs() as f64, Err(until_epoch) => -(until_epoch.duration().as_secs() as f64), } } /// Be able to restore the term's foreground process group. /// This is set during startup and not modified after. static INITIAL_FG_PROCESS_GROUP: AtomicI32 = AtomicI32::new(-1); // HACK, should be pid_t const _: () = assert!(mem::size_of::() >= mem::size_of::()); /// Save the value of tcgetpgrp so we can restore it on exit. pub fn save_term_foreground_process_group() { INITIAL_FG_PROCESS_GROUP.store(unsafe { libc::tcgetpgrp(STDIN_FILENO) }, Ordering::Relaxed); } pub fn restore_term_foreground_process_group_for_exit() { // We wish to restore the tty to the initial owner. There's two ways this can go wrong: // 1. We may steal the tty from someone else (#7060). // 2. The call to tcsetpgrp may deliver SIGSTOP to us, and we will not exit. // Hanging on exit seems worse, so ensure that SIGTTOU is ignored so we do not get SIGSTOP. // Note initial_fg_process_group == 0 is possible with Linux pid namespaces. // This is called during shutdown and from a signal handler. We don't bother to complain on // failure because doing so is unlikely to be noticed. // Safety: All of getpgrp, signal, and tcsetpgrp are async-signal-safe. let initial_fg_process_group = INITIAL_FG_PROCESS_GROUP.load(Ordering::Relaxed); if initial_fg_process_group > 0 && initial_fg_process_group != unsafe { libc::getpgrp() } { unsafe { libc::signal(SIGTTOU, SIG_IGN); libc::tcsetpgrp(STDIN_FILENO, initial_fg_process_group); } } } #[allow(unused)] // This function is unused in some configurations/on some platforms fn slice_contains_slice(a: &[T], b: &[T]) -> bool { subslice_position(a, b).is_some() } pub fn subslice_position(a: &[T], b: &[T]) -> Option { if b.is_empty() { return Some(0); } a.windows(b.len()).position(|aw| aw == b) } #[derive(Copy, Debug, Clone, PartialEq, Eq)] pub enum WSL { Any, V1, V2, } /// Determines if we are running under Microsoft's Windows Subsystem for Linux to work around /// some known limitations and/or bugs. /// /// See https://github.com/Microsoft/WSL/issues/423 and Microsoft/WSL#2997 #[inline(always)] #[cfg(not(target_os = "linux"))] pub fn is_windows_subsystem_for_linux(_: WSL) -> bool { false } /// Determines if we are running under Microsoft's Windows Subsystem for Linux to work around /// some known limitations and/or bugs. /// /// See https://github.com/Microsoft/WSL/issues/423 and Microsoft/WSL#2997 #[cfg(target_os = "linux")] pub fn is_windows_subsystem_for_linux(v: WSL) -> bool { use std::sync::OnceLock; static RESULT: OnceLock> = OnceLock::new(); // This is called post-fork from [`report_setpgid_error()`], so the fast path must not involve // any allocations or mutexes. We can't rely on all the std functions to be alloc-free in both // Debug and Release modes, so we just mandate that the result already be available. // // is_wsl() is called by has_working_timestamps() which is called by `screen.cpp` in the main // process. If that's not good enough, we can call is_wsl() manually at shell startup. if crate::threads::is_forked_child() { debug_assert!( RESULT.get().is_some(), "is_wsl() should be called by main before forking!" ); } let wsl = RESULT.get_or_init(|| { let mut info: libc::utsname = unsafe { mem::zeroed() }; let release: &[u8] = unsafe { libc::uname(&mut info); std::mem::transmute(&info.release[..]) }; // Sample utsname.release under WSLv2, testing for something like `4.19.104-microsoft-standard` // or `5.10.16.3-microsoft-standard-WSL2` if slice_contains_slice(release, b"microsoft-standard") { return Some(WSL::V2); } // Sample utsname.release under WSL, testing for something like `4.4.0-17763-Microsoft` if !slice_contains_slice(release, b"Microsoft") { return None; } let release: Vec<_> = release .iter() .copied() .skip_while(|c| *c != b'-') .skip(1) // the dash itself .take_while(|c| c.is_ascii_digit()) .collect(); let build: Result = std::str::from_utf8(&release).unwrap().parse(); match build { Ok(17763..) => return Some(WSL::V1), Ok(_) => (), // return true, but first warn (see below) _ => return None, // if parsing fails, assume this isn't WSL }; // #5298, #5661: There are acknowledged, published, and (later) fixed issues with // job control under early WSL releases that prevent fish from running correctly, // with unexpected failures when piping. Fish 3.0 nightly builds worked around this // issue with some needlessly complicated code that was later stripped from the // fish 3.0 release, so we just bail. Note that fish 2.0 was also broken, but we // just didn't warn about it. // #6038 & 5101bde: It's been requested that there be some sort of way to disable // this check: if the environment variable FISH_NO_WSL_CHECK is present, this test // is bypassed. We intentionally do not include this in the error message because // it'll only allow fish to run but not to actually work. Here be dragons! use crate::flog::FLOG; if env::var_os("FISH_NO_WSL_CHECK").is_none() { FLOG!( error, concat!( "This version of WSL has known bugs that prevent fish from working.\n", "Please upgrade to Windows 10 1809 (17763) or higher to use fish!" ) ); } Some(WSL::V1) }); wsl.map(|wsl| v == WSL::Any || wsl == v).unwrap_or(false) } /// Return true if the character is in a range reserved for fish's private use. /// /// NOTE: This is used when tokenizing the input. It is also used when reading input, before /// tokenization, to replace such chars with REPLACEMENT_WCHAR if they're not part of a quoted /// string. We don't want external input to be able to feed reserved characters into our /// lexer/parser or code evaluator. // // TODO: Actually implement the replacement as documented above. pub fn fish_reserved_codepoint(c: char) -> bool { (c >= RESERVED_CHAR_BASE && c < RESERVED_CHAR_END) || (c >= key::Backspace && c < ENCODE_DIRECT_END) } pub fn redirect_tty_output() { unsafe { let mut t: libc::termios = mem::zeroed(); let s = CString::new("/dev/null").unwrap(); let fd = libc::open(s.as_ptr(), O_WRONLY); assert!(fd != -1, "Could not open /dev/null!"); for stdfd in [STDIN_FILENO, STDOUT_FILENO, STDERR_FILENO] { if libc::tcgetattr(stdfd, &mut t) == -1 && errno::errno().0 == EIO { libc::dup2(fd, stdfd); } } } } /// Test if the given char is valid in a variable name. pub fn valid_var_name_char(chr: char) -> bool { fish_iswalnum(chr) || chr == '_' } /// Test if the given string is a valid variable name. pub fn valid_var_name(s: &wstr) -> bool { // Note do not use c_str(), we want to fail on embedded nul bytes. !s.is_empty() && s.chars().all(valid_var_name_char) } /// Get the absolute path to the fish executable itself pub fn get_executable_path(argv0: impl AsRef) -> PathBuf { if let Ok(path) = std::env::current_exe() { if path.exists() { return path; } // When /proc/self/exe points to a file that was deleted (or overwritten on update!) // then linux adds a " (deleted)" suffix. // If that's not a valid path, let's remove that awkward suffix. if !path.ends_with(" (deleted)") { return path; } if let (Some(filename), Some(parent)) = (path.file_name(), path.parent()) { if let Some(filename) = filename.to_str() { let corrected_filename = OsStr::new(filename.strip_suffix(" (deleted)").unwrap()); return parent.join(corrected_filename); } } return path; } argv0.as_ref().to_owned() } /// A RAII cleanup object. Unlike in C++ where there is no borrow checker, we can't just provide a /// callback that modifies live objects willy-nilly because then there would be two &mut references /// to the same object - the original variables we keep around to use and their captured references /// held by the closure until its scope expires. /// /// Instead we have a `ScopeGuard` type that takes exclusive ownership of (a mutable reference to) /// the object to be managed. In lieu of keeping the original value around, we obtain a regular or /// mutable reference to it via ScopeGuard's [`Deref`] and [`DerefMut`] impls. /// /// The `ScopeGuard` is considered to be the exclusively owner of the passed value for the /// duration of its lifetime. If you need to use the value again, use `ScopeGuard` to shadow the /// value and obtain a reference to it via the `ScopeGuard` itself: /// /// ```rust /// use std::io::prelude::*; /// use fish::common::ScopeGuard; /// /// let file = std::fs::File::create("/dev/null").unwrap(); /// // Create a scope guard to write to the file when the scope expires. /// // To be able to still use the file, shadow `file` with the ScopeGuard itself. /// let mut file = ScopeGuard::new(file, |file| file.write_all(b"goodbye\n").unwrap()); /// // Now write to the file normally "through" the capturing ScopeGuard instance. /// file.write_all(b"hello\n").unwrap(); /// /// // hello will be written first, then goodbye. /// ``` pub struct ScopeGuard(Option<(T, F)>); impl ScopeGuard { /// Creates a new `ScopeGuard` wrapping `value`. The `on_drop` callback is executed when the /// ScopeGuard's lifetime expires or when it is manually dropped. pub fn new(value: T, on_drop: F) -> Self { Self(Some((value, on_drop))) } /// Invokes the callback and returns the wrapped value, consuming the ScopeGuard. pub fn commit(mut guard: Self) -> T { let (mut value, on_drop) = guard.0.take().expect("Should always have Some value"); on_drop(&mut value); value } /// Cancels the invocation of the callback, returning the original wrapped value. pub fn cancel(mut guard: Self) -> T { let (value, _) = guard.0.take().expect("Should always have Some value"); value } } impl Deref for ScopeGuard { type Target = T; fn deref(&self) -> &Self::Target { &self.0.as_ref().unwrap().0 } } impl DerefMut for ScopeGuard { fn deref_mut(&mut self) -> &mut Self::Target { &mut self.0.as_mut().unwrap().0 } } impl Drop for ScopeGuard { fn drop(&mut self) { if let Some((mut value, on_drop)) = self.0.take() { on_drop(&mut value); } } } /// A trait expressing what ScopeGuard can do. This is necessary because scoped_push returns an /// `impl Trait` object and therefore methods on ScopeGuard which take a self parameter cannot be /// used. pub trait ScopeGuarding: DerefMut { /// Invokes the callback and returns the wrapped value, consuming the ScopeGuard. fn commit(guard: Self) -> Self::Target; } impl ScopeGuarding for ScopeGuard { fn commit(guard: Self) -> T { ScopeGuard::commit(guard) } } /// A scoped manager to save the current value of some variable, and set it to a new value. When /// dropped, it restores the variable to its old value. pub fn scoped_push( mut ctx: Context, accessor: Accessor, new_value: T, ) -> impl ScopeGuarding where Accessor: Fn(&mut Context) -> &mut T, { let saved = mem::replace(accessor(&mut ctx), new_value); let restore_saved = move |ctx: &mut Context| { *accessor(ctx) = saved; }; ScopeGuard::new(ctx, restore_saved) } /// Similar to scoped_push but takes a function like "std::mem::replace" instead of a function /// that returns a mutable reference. pub fn scoped_push_replacer( replacer: Replacer, new_value: T, ) -> impl ScopeGuarding where Replacer: Fn(T) -> T, { let saved = replacer(new_value); let restore_saved = move |_ctx: &mut ()| { replacer(saved); }; ScopeGuard::new((), restore_saved) } pub fn scoped_push_replacer_ctx( mut ctx: Context, replacer: Replacer, new_value: T, ) -> impl ScopeGuarding where Replacer: Fn(&mut Context, T) -> T, { let saved = replacer(&mut ctx, new_value); let restore_saved = move |ctx: &mut Context| { replacer(ctx, saved); }; ScopeGuard::new(ctx, restore_saved) } pub const fn assert_send() {} pub const fn assert_sync() {} /// This function attempts to distinguish between a console session (at the actual login vty) and a /// session within a terminal emulator inside a desktop environment or over SSH. Unfortunately /// there are few values of $TERM that we can interpret as being exclusively console sessions, and /// most common operating systems do not use them. The value is cached for the duration of the fish /// session. We err on the side of assuming it's not a console session. This approach isn't /// bullet-proof and that's OK. pub fn is_console_session() -> bool { static IS_CONSOLE_SESSION: OnceCell = OnceCell::new(); *IS_CONSOLE_SESSION.get_or_init(|| { const PATH_MAX: usize = libc::PATH_MAX as usize; let mut tty_name = [0u8; PATH_MAX]; unsafe { if libc::ttyname_r(STDIN_FILENO, tty_name.as_mut_ptr().cast(), tty_name.len()) != 0 { return false; } } // Check if the tty matches /dev/(console|dcons|tty[uv\d]) const LEN: usize = b"/dev/tty".len(); ( ( tty_name.starts_with(b"/dev/tty") && ([b'u', b'v'].contains(&tty_name[LEN]) || tty_name[LEN].is_ascii_digit()) ) || tty_name.starts_with(b"/dev/dcons\0") || tty_name.starts_with(b"/dev/console\0")) // and that $TERM is simple, e.g. `xterm` or `vt100`, not `xterm-something` or `sun-color`. && match env::var_os("TERM") { Some(term) => !term.as_bytes().contains(&b'-'), None => true, } }) } /// Asserts that a slice is alphabetically sorted by a [`&wstr`] `name` field. /// /// Mainly useful for static asserts/const eval. /// /// # Panics /// /// This function panics if the given slice is unsorted. /// /// # Examples /// /// ``` /// use fish::wchar::prelude::*; /// use fish::assert_sorted_by_name; /// /// const COLORS: &[(&wstr, u32)] = &[ /// // must be in alphabetical order /// (L!("blue"), 0x0000ff), /// (L!("green"), 0x00ff00), /// (L!("red"), 0xff0000), /// ]; /// /// assert_sorted_by_name!(COLORS, 0); /// ``` /// /// While this example would fail to compile: /// /// ```compile_fail /// use fish::wchar::prelude::*; /// use fish::assert_sorted_by_name; /// /// const COLORS: &[(&wstr, u32)] = &[ /// // not in alphabetical order /// (L!("green"), 0x00ff00), /// (L!("blue"), 0x0000ff), /// (L!("red"), 0xff0000), /// ]; /// /// assert_sorted_by_name!(COLORS, 0); /// ``` #[macro_export] macro_rules! assert_sorted_by_name { ($slice:expr, $field:tt) => { const _: () = { use std::cmp::Ordering; // ugly const eval workarounds below. const fn cmp_i32(lhs: i32, rhs: i32) -> Ordering { match lhs - rhs { ..=-1 => Ordering::Less, 0 => Ordering::Equal, 1.. => Ordering::Greater, } } const fn cmp_slice(s1: &[char], s2: &[char]) -> Ordering { let mut i = 0; while i < s1.len() && i < s2.len() { match cmp_i32(s1[i] as i32, s2[i] as i32) { Ordering::Equal => i += 1, other => return other, } } cmp_i32(s1.len() as i32, s2.len() as i32) } let mut i = 1; while i < $slice.len() { let prev = $slice[i - 1].$field.as_char_slice(); let cur = $slice[i].$field.as_char_slice(); if matches!(cmp_slice(prev, cur), Ordering::Greater) { panic!("array must be sorted"); } i += 1; } }; }; ($slice:expr) => { assert_sorted_by_name!($slice, name); }; } pub trait Named { fn name(&self) -> &'static wstr; } /// Return a pointer to the first entry with the given name, assuming the entries are sorted by /// name. Return nullptr if not found. pub fn get_by_sorted_name(name: &wstr, vals: &'static [T]) -> Option<&'static T> { match vals.binary_search_by_key(&name, |val| val.name()) { Ok(index) => Some(&vals[index]), Err(_) => None, } } /// A trait to make it more convenient to pass ascii/Unicode strings to functions that can take /// non-Unicode values. The result is nul-terminated and can be passed to OS functions. /// /// This is only implemented for owned types where an owned instance will skip allocations (e.g. /// `CString` can return `self`) but not implemented for owned instances where a new allocation is /// always required (e.g. implemented for `&wstr` but not `WideString`) because you might as well be /// left with the original item if we're going to allocate from scratch in all cases. pub trait ToCString { /// Correctly convert to a nul-terminated [`CString`] that can be passed to OS functions. fn to_cstring(self) -> CString; } impl ToCString for CString { fn to_cstring(self) -> CString { self } } impl ToCString for &CStr { fn to_cstring(self) -> CString { self.to_owned() } } /// Safely converts from `&wstr` to a `CString` to a nul-terminated `CString` that can be passed to /// OS functions, taking into account non-Unicode values that have been shifted into the private-use /// range by using [`wcs2zstring()`]. impl ToCString for &wstr { /// The wide string may contain non-Unicode bytes mapped to the private-use Unicode range, so we /// have to use [`wcs2zstring()`](self::wcs2zstring) to convert it correctly. fn to_cstring(self) -> CString { self::wcs2zstring(self) } } /// Safely converts from `&WString` to a nul-terminated `CString` that can be passed to OS /// functions, taking into account non-Unicode values that have been shifted into the private-use /// range by using [`wcs2zstring()`]. impl ToCString for &WString { fn to_cstring(self) -> CString { self.as_utfstr().to_cstring() } } /// Convert a (probably ascii) string to CString that can be passed to OS functions. impl ToCString for Vec { fn to_cstring(mut self) -> CString { self.push(b'\0'); CString::from_vec_with_nul(self).unwrap() } } /// Convert a (probably ascii) string to nul-terminated CString that can be passed to OS functions. impl ToCString for &[u8] { fn to_cstring(self) -> CString { CString::new(self).unwrap() } }