//! String expansion functions. These functions perform several kinds of parameter expansion. There //! are a lot of issues with regards to memory allocation. Overall, these functions would benefit //! from using a more clever memory allocation scheme, perhaps an evil combination of talloc, //! string buffers and reference counting. use crate::builtins::shared::{ STATUS_CMD_ERROR, STATUS_CMD_UNKNOWN, STATUS_EXPAND_ERROR, STATUS_ILLEGAL_CMD, STATUS_INVALID_ARGS, STATUS_NOT_EXECUTABLE, STATUS_READ_TOO_MUCH, STATUS_UNMATCHED_WILDCARD, }; use crate::common::{ char_offset, charptr2wcstring, escape, escape_string, escape_string_for_double_quotes, unescape_string, valid_var_name_char, wcs2zstring, EscapeFlags, EscapeStringStyle, UnescapeFlags, UnescapeStringStyle, EXPAND_RESERVED_BASE, EXPAND_RESERVED_END, }; use crate::complete::{CompleteFlags, Completion, CompletionList, CompletionReceiver}; use crate::env::{EnvVar, Environment}; use crate::exec::exec_subshell_for_expand; use crate::future_feature_flags::{feature_test, FeatureFlag}; use crate::history::{history_session_id, History}; use crate::operation_context::OperationContext; use crate::parse_constants::{ParseError, ParseErrorCode, ParseErrorList, SOURCE_LOCATION_UNKNOWN}; use crate::parse_util::{ parse_util_expand_variable_error, parse_util_locate_cmdsubst_range, MaybeParentheses, }; use crate::path::path_apply_working_directory; use crate::util::wcsfilecmp_glob; use crate::wchar::prelude::*; use crate::wcstringutil::{join_strings, trim}; use crate::wildcard::{wildcard_expand_string, wildcard_has_internal}; use crate::wildcard::{WildcardResult, ANY_CHAR, ANY_STRING, ANY_STRING_RECURSIVE}; use crate::wutil::{normalize_path, wcstoi_partial, Options}; use bitflags::bitflags; bitflags! { /// Set of flags controlling expansions. #[derive(Copy, Clone, Default)] pub struct ExpandFlags : u16 { /// Fail expansion if there is a command substitution. const FAIL_ON_CMDSUBST = 1 << 0; /// Skip command substitutions. const SKIP_CMDSUBST = 1 << 14; /// Skip variable expansion. const SKIP_VARIABLES = 1 << 1; /// Skip wildcard expansion. const SKIP_WILDCARDS = 1 << 2; /// The expansion is being done for tab or auto completions. Returned completions may have the /// wildcard as a prefix instead of a match. const FOR_COMPLETIONS = 1 << 3; /// Only match files that are executable by the current user. const EXECUTABLES_ONLY = 1 << 4; /// Only match directories. const DIRECTORIES_ONLY = 1 << 5; /// Generate descriptions, stored in the description field of completions. const GEN_DESCRIPTIONS = 1 << 6; /// Un-expand home directories to tildes after. const PRESERVE_HOME_TILDES = 1 << 7; /// Allow fuzzy matching. const FUZZY_MATCH = 1 << 8; /// Disallow directory abbreviations like /u/l/b for /usr/local/bin. Only applicable if /// fuzzy_match is set. const NO_FUZZY_DIRECTORIES = 1 << 9; /// Allows matching a leading dot even if the wildcard does not contain one. /// By default, wildcards only match a leading dot literally; this is why e.g. '*' does not /// match hidden files. const ALLOW_NONLITERAL_LEADING_DOT = 1 << 10; /// Do expansions specifically to support cd. This means using CDPATH as a list of potential /// working directories, and to use logical instead of physical paths. const SPECIAL_FOR_CD = 1 << 11; /// Do expansions specifically for cd autosuggestion. This is to differentiate between cd /// completions and cd autosuggestions. const SPECIAL_FOR_CD_AUTOSUGGESTION = 1 << 12; /// Do expansions specifically to support external command completions. This means using PATH as /// a list of potential working directories. const SPECIAL_FOR_COMMAND = 1 << 13; } } /// Character representing a home directory. pub const HOME_DIRECTORY: char = char_offset(EXPAND_RESERVED_BASE, 0); /// Character representing process expansion for %self. pub const PROCESS_EXPAND_SELF: char = char_offset(EXPAND_RESERVED_BASE, 1); /// Character representing variable expansion. pub const VARIABLE_EXPAND: char = char_offset(EXPAND_RESERVED_BASE, 2); /// Character representing variable expansion into a single element. pub const VARIABLE_EXPAND_SINGLE: char = char_offset(EXPAND_RESERVED_BASE, 3); /// Character representing the start of a bracket expansion. pub const BRACE_BEGIN: char = char_offset(EXPAND_RESERVED_BASE, 4); /// Character representing the end of a bracket expansion. pub const BRACE_END: char = char_offset(EXPAND_RESERVED_BASE, 5); /// Character representing separation between two bracket elements. pub const BRACE_SEP: char = char_offset(EXPAND_RESERVED_BASE, 6); /// Character that takes the place of any whitespace within non-quoted text in braces pub const BRACE_SPACE: char = char_offset(EXPAND_RESERVED_BASE, 7); /// Separate subtokens in a token with this character. pub const INTERNAL_SEPARATOR: char = char_offset(EXPAND_RESERVED_BASE, 8); /// Character representing an empty variable expansion. Only used transitively while expanding /// variables. pub const VARIABLE_EXPAND_EMPTY: char = char_offset(EXPAND_RESERVED_BASE, 9); const _: () = assert!( EXPAND_RESERVED_END as u32 > VARIABLE_EXPAND_EMPTY as u32, "Characters used in expansions must stay within private use area" ); impl ExpandResult { pub fn new(result: ExpandResultCode) -> Self { Self { result, status: 0 } } pub fn ok() -> Self { Self::new(ExpandResultCode::ok) } /// Make an error value with the given status. pub fn make_error(status: libc::c_int) -> Self { assert!(status != 0, "status cannot be 0 for an error result"); Self { result: ExpandResultCode::error, status, } } } impl PartialEq for ExpandResult { fn eq(&self, other: &ExpandResultCode) -> bool { self.result == *other } } /// The string represented by PROCESS_EXPAND_SELF pub const PROCESS_EXPAND_SELF_STR: &wstr = L!("%self"); /// Perform various forms of expansion on in, such as tilde expansion (\~USER becomes the users home /// directory), variable expansion (\$VAR_NAME becomes the value of the environment variable /// VAR_NAME), cmdsubst expansion and wildcard expansion. The results are inserted into the list /// out. /// /// If the parameter does not need expansion, it is copied into the list out. /// /// \param input The parameter to expand /// \param output The list to which the result will be appended. /// \param ctx The parser, variables, and cancellation checker for this operation. The parser may /// be null. \param errors Resulting errors, or nullptr to ignore /// /// Return An expand_result_t. /// wildcard_no_match and wildcard_match are normal exit conditions used only on /// strings containing wildcards to tell if the wildcard produced any matches. pub fn expand_string( input: WString, out_completions: &mut CompletionList, flags: ExpandFlags, ctx: &OperationContext, errors: Option<&mut ParseErrorList>, ) -> ExpandResult { let mut completions = vec![]; std::mem::swap(&mut completions, out_completions); let mut recv = CompletionReceiver::from_list(completions, ctx.expansion_limit); let result = expand_to_receiver(input, &mut recv, flags, ctx, errors); *out_completions = recv.take(); result } /// Variant of string that inserts its results into a completion_receiver_t. pub fn expand_to_receiver( input: WString, out_completions: &mut CompletionReceiver, flags: ExpandFlags, ctx: &OperationContext, errors: Option<&mut ParseErrorList>, ) -> ExpandResult { Expander::expand_string(input, out_completions, flags, ctx, errors) } /// expand_one is identical to expand_string, except it will fail if in expands to more than one /// string. This is used for expanding command names. /// /// \param inout_str The parameter to expand in-place /// \param ctx The parser, variables, and cancellation checker for this operation. The parser may be /// null. /// \param errors Resulting errors, or nullptr to ignore /// /// Return Whether expansion succeeded. pub fn expand_one( s: &mut WString, flags: ExpandFlags, ctx: &OperationContext, errors: Option<&mut ParseErrorList>, ) -> bool { let mut completions = CompletionList::new(); if !flags.contains(ExpandFlags::FOR_COMPLETIONS) && expand_is_clean(s) { return true; } let mut tmp = WString::new(); std::mem::swap(s, &mut tmp); if expand_string(tmp, &mut completions, flags, ctx, errors) == ExpandResultCode::ok && completions.len() == 1 { std::mem::swap(s, &mut completions[0].completion); return true; } false } /// Expand a command string like $HOME/bin/cmd into a command and list of arguments. /// Return the command and arguments by reference. /// If the expansion resulted in no or an empty command, the command will be an empty string. Note /// that API does not distinguish between expansion resulting in an empty command (''), and /// expansion resulting in no command (e.g. unset variable). /// If `skip_wildcards` is true, then do not do wildcard expansion /// Return an expand error. pub fn expand_to_command_and_args( instr: &wstr, ctx: &OperationContext<'_>, out_cmd: &mut WString, mut out_args: Option<&mut Vec>, errors: Option<&mut ParseErrorList>, skip_wildcards: bool, ) -> ExpandResult { // Fast path. if expand_is_clean(instr) { *out_cmd = instr.to_owned(); return ExpandResult::ok(); } let mut eflags = ExpandFlags::FAIL_ON_CMDSUBST; if skip_wildcards { eflags |= ExpandFlags::SKIP_WILDCARDS; } let mut completions = CompletionList::new(); let expand_err = expand_string(instr.to_owned(), &mut completions, eflags, ctx, errors); if expand_err == ExpandResultCode::ok { // The first completion is the command, any remaining are arguments. let mut completions = completions.into_iter(); if let Some(comp) = completions.next() { *out_cmd = comp.completion; } if let Some(ref mut out_args) = out_args { for comp in completions { out_args.push(comp.completion); } } } expand_err } /// Convert the variable value to a human readable form, i.e. escape things, handle arrays, etc. /// Suitable for pretty-printing. pub fn expand_escape_variable(var: &EnvVar) -> WString { let mut buff = WString::new(); let lst = var.as_list(); for el in lst { if !buff.is_empty() { buff.push_str(" "); } // We want to use quotes if we have more than one string, or the string contains a space. let prefer_quotes = lst.len() > 1 || el.contains(' '); if prefer_quotes && is_quotable(el) { buff.push('\''); buff.push_utfstr(el); buff.push('\''); } else { buff.push_utfstr(&escape(el)); } } buff } /// Convert a string value to a human readable form, i.e. escape things, handle arrays, etc. /// Suitable for pretty-printing. pub fn expand_escape_string(el: &wstr) -> WString { let mut buff = WString::new(); let prefer_quotes = el.contains(' '); if prefer_quotes && is_quotable(el) { buff.push('\''); buff.push_utfstr(el); buff.push('\''); } else { buff.push_utfstr(&escape(el)); } buff } /// Perform tilde expansion and nothing else on the specified string, which is modified in place. /// /// \param input the string to tilde expand pub fn expand_tilde(input: &mut WString, vars: &dyn Environment) { if input.chars().next() == Some('~') { input.replace_range(0..1, wstr::from_char_slice(&[HOME_DIRECTORY])); expand_home_directory(input, vars); } } /// Perform the opposite of tilde expansion on the string, which is modified in place. pub fn replace_home_directory_with_tilde(s: &wstr, vars: &dyn Environment) -> WString { let mut result = s.to_owned(); // Only absolute paths get this treatment. if result.starts_with(L!("/")) { let mut home_directory = L!("~").to_owned(); expand_tilde(&mut home_directory, vars); // If we can't get a home directory, don't replace anything. // This is the case e.g. with --no-execute if home_directory.is_empty() { return result; } if !home_directory.ends_with(L!("/")) { home_directory.push('/'); } // Now check if the home_directory prefixes the string. if result.starts_with(&home_directory) { // Success result.replace_range(0..home_directory.len(), L!("~/")); } } result } /// Characters which make a string unclean if they are the first character of the string. See \c /// expand_is_clean(). const UNCLEAN_FIRST: &wstr = L!("~%"); /// Unclean characters. See \c expand_is_clean(). const UNCLEAN: &wstr = L!("$*?\\\"'({})"); /// Test if the specified argument is clean, i.e. it does not contain any tokens which need to be /// expanded or otherwise altered. Clean strings can be passed through expand_string and expand_one /// without changing them. About two thirds of all strings are clean, so skipping expansion on them /// actually does save a small amount of time, since it avoids multiple memory allocations during /// the expansion process. /// /// \param in the string to test fn expand_is_clean(input: &wstr) -> bool { if input.is_empty() { return true; } // Test characters that have a special meaning in the first character position. if UNCLEAN_FIRST.contains(input.as_char_slice()[0]) { return false; } // Test characters that have a special meaning in any character position. !input.chars().any(|c| UNCLEAN.contains(c)) } /// Append a syntax error to the given error list. macro_rules! append_syntax_error { ( $errors:expr, $source_start:expr, $fmt:expr $(, $arg:expr )* $(,)? ) => { if let Some(ref mut errors) = $errors { let mut error = ParseError::default(); error.source_start = $source_start; error.source_length = 0; error.code = ParseErrorCode::syntax; error.text = wgettext_maybe_fmt!($fmt $(, $arg)*); errors.push(error); } } } /// Append a cmdsub error to the given error list. But only do so if the error hasn't already been /// recorded. This is needed because command substitution is a recursive process and some errors /// could consequently be recorded more than once. macro_rules! append_cmdsub_error { ( $errors:expr, $source_start:expr, $source_end:expr, $fmt:expr $(, $arg:expr )* $(,)? ) => { append_cmdsub_error_formatted!( $errors, $source_start, $source_end, wgettext_maybe_fmt!($fmt $(, $arg)*)); } } macro_rules! append_cmdsub_error_formatted { ( $errors:expr, $source_start:expr, $source_end:expr, $text:expr $(,)? ) => { if let Some(ref mut errors) = $errors { let mut error = ParseError::default(); error.source_start = $source_start; error.source_length = $source_end - $source_start + 1; error.code = ParseErrorCode::cmdsubst; error.text = $text; if !errors.iter().any(|e| e.text == error.text) { errors.push(error); } } }; } /// Append an overflow error, when expansion produces too much data. fn append_overflow_error( errors: &mut Option<&mut ParseErrorList>, source_start: Option, ) -> ExpandResult { if let Some(ref mut errors) = errors { let mut error = ParseError::default(); error.source_start = source_start.unwrap_or(SOURCE_LOCATION_UNKNOWN); error.source_length = 0; error.code = ParseErrorCode::generic; error.text = wgettext!("Expansion produced too many results").to_owned(); errors.push(error); } ExpandResult::make_error(STATUS_EXPAND_ERROR.unwrap()) } /// Test if the specified string does not contain character which can not be used inside a quoted /// string. fn is_quotable(s: &wstr) -> bool { !s.chars().any(|c| "\n\t\r\x08\x1B".contains(c)) } enum ParseSliceError { zero_index, invalid_index, } /// Parse an array slicing specification Returns 0 on success. If a parse error occurs, returns the /// index of the bad token. Note that 0 can never be a bad index because the string always starts /// with [. fn parse_slice( input: &wstr, idx: &mut Vec, array_size: usize, ) -> Result { let size = i64::try_from(array_size).unwrap(); let mut pos = 1; // skip past the opening square bracket loop { while input.char_at(pos).is_whitespace() || input.char_at(pos) == INTERNAL_SEPARATOR { pos += 1; } if input.char_at(pos) == ']' { pos += 1; break; } let tmp = if idx.is_empty() && input.char_at(pos) == '.' && input.char_at(pos + 1) == '.' { // If we are at the first index expression, a missing start-index means the range starts // at the first item. 1 // first index } else { let mut consumed = 0; match wcstoi_partial(&input[pos..], Options::default(), &mut consumed) { Ok(tmp) => { if tmp == 0 { // Explicitly refuse $foo[0] as valid syntax, regardless of whether or // not we're going to show an error if the index ultimately evaluates // to zero. This will help newcomers to fish avoid a common off-by-one // error. See #4862. return Err((pos, ParseSliceError::zero_index)); } pos += consumed; // Skip trailing whitespace. pos += input[pos..] .chars() .take_while(|c| c.is_whitespace()) .count(); tmp } Err(_error) => { // We don't test `*end` as is typically done because we expect it to not // be the null char. Ignore the case of errno==-1 because it means the end // char wasn't the null char. return Err((pos, ParseSliceError::invalid_index)); } } }; let mut i1 = if tmp > -1 { tmp } else { size + tmp + 1 }; while input.char_at(pos) == INTERNAL_SEPARATOR { pos += 1; } if input.char_at(pos) == '.' && input.char_at(pos + 1) == '.' { pos += 2; while input.char_at(pos) == INTERNAL_SEPARATOR { pos += 1; } while input.char_at(pos).is_whitespace() { pos += 1; // Allow the space in "[.. ]". } // If we are at the last index range expression then a missing end-index means the // range spans until the last item. let tmp1 = if input.char_at(pos) == ']' { -1 // last index } else { let mut consumed = 0; match wcstoi_partial(&input[pos..], Options::default(), &mut consumed) { Ok(tmp) => { if tmp == 0 { return Err((pos, ParseSliceError::zero_index)); } pos += consumed; // Skip trailing whitespace. pos += input[pos..] .chars() .take_while(|c| c.is_whitespace()) .count(); tmp } Err(_error) => { return Err((pos, ParseSliceError::invalid_index)); } } }; let mut i2 = if tmp1 > -1 { tmp1 } else { size + tmp1 + 1 }; // Skip sequences that are entirely outside. // This means "17..18" expands to nothing if there are less than 17 elements. if i1 > size && i2 > size { continue; } let mut direction = if i2 < i1 { -1 } else { 1 }; // If only the beginning is negative, always go reverse. // If only the end, always go forward. // Prevents `[x..-1]` from going reverse if less than x elements are there. if (tmp1 > -1) != (tmp > -1) { direction = if tmp1 > -1 { -1 } else { 1 }; } else { // Clamp to array size when not forcing direction // - otherwise "2..-1" clamps both to 1 and then becomes "1..1". i1 = i1.min(size); i2 = i2.min(size); } let mut jjj = i1; while jjj * direction <= i2 * direction { idx.push(jjj); jjj += direction; } continue; } idx.push(i1); } Ok(pos) } /// Expand all environment variables in the string *ptr. /// /// This function is slow, fragile and complicated. There are lots of little corner cases, like /// $$foo should do a double expansion, $foo$bar should not double expand bar, etc. /// /// This function operates on strings backwards, starting at last_idx. /// /// Note: last_idx is considered to be where it previously finished processing. This means it /// actually starts operating on last_idx-1. As such, to process a string fully, pass string.size() /// as last_idx instead of string.size()-1. /// /// Return the result of expansion. fn expand_variables( instr: WString, out: &mut CompletionReceiver, last_idx: usize, vars: &dyn Environment, errors: &mut Option<&mut ParseErrorList>, ) -> ExpandResult { // last_idx may be 1 past the end of the string, but no further. assert!(last_idx <= instr.len(), "Invalid last_idx"); if last_idx == 0 { if !out.add(instr) { return append_overflow_error(errors, None); } return ExpandResult::ok(); } // Locate the last VARIABLE_EXPAND or VARIABLE_EXPAND_SINGLE let mut is_single = false; let mut varexp_char_idx = last_idx; loop { let done = varexp_char_idx == 0; varexp_char_idx = varexp_char_idx.wrapping_sub(1); if done { break; } let c = instr.as_char_slice()[varexp_char_idx]; if [VARIABLE_EXPAND, VARIABLE_EXPAND_SINGLE].contains(&c) { is_single = c == VARIABLE_EXPAND_SINGLE; break; } } if varexp_char_idx == usize::MAX { // No variable expand char, we're done. if !out.add(instr) { return append_overflow_error(errors, None); } return ExpandResult::ok(); } // Get the variable name. let var_name_start = varexp_char_idx + 1; let mut var_name_stop = var_name_start; while var_name_stop < instr.len() { let nc = instr.as_char_slice()[var_name_stop]; if nc == VARIABLE_EXPAND_EMPTY { var_name_stop += 1; break; } if !valid_var_name_char(nc) { break; } var_name_stop += 1; } assert!( var_name_stop >= var_name_start, "Bogus variable name indexes" ); // Get the variable name as a string, then try to get the variable from env. let var_name = &instr[var_name_start..var_name_stop]; // It's an error if the name is empty. if var_name.is_empty() { if let Some(ref mut errors) = errors { parse_util_expand_variable_error( &instr, 0, /* global_token_pos */ varexp_char_idx, errors, ); } return ExpandResult::make_error(STATUS_EXPAND_ERROR.unwrap()); } // Do a dirty hack to make sliced history fast (#4650). We expand from either a variable, or a // history_t. Note that "history" is read only in env.cpp so it's safe to special-case it in // this way (it cannot be shadowed, etc). let mut history = None; let mut var = None; if var_name == "history" { history = Some(History::with_name(&history_session_id(vars))); } else if var_name.as_char_slice() != [VARIABLE_EXPAND_EMPTY] { var = vars.get(var_name); } // Parse out any following slice. // Record the end of the variable name and any following slice. let mut var_name_and_slice_stop = var_name_stop; let mut all_values = true; let slice_start = var_name_stop; let mut var_idx_list = vec![]; if instr.as_char_slice().get(slice_start) == Some(&'[') { all_values = false; // If a variable is missing, behave as though we have one value, so that $var[1] always // works. let mut effective_val_count = 1; if let Some(ref var) = var { effective_val_count = var.as_list().len(); } else if let Some(ref history) = history { effective_val_count = history.size(); } match parse_slice( &instr[slice_start..], &mut var_idx_list, effective_val_count, ) { Ok(offset) => { var_name_and_slice_stop = slice_start + offset; } Err((bad_pos, error)) => { match error { ParseSliceError::zero_index => { append_syntax_error!( errors, slice_start + bad_pos, "array indices start at 1, not 0." ); } ParseSliceError::invalid_index => { append_syntax_error!(errors, slice_start + bad_pos, "Invalid index value"); } } return ExpandResult::make_error(STATUS_EXPAND_ERROR.unwrap()); } } } let var_idx_list = var_idx_list.iter().filter_map(|&n| n.try_into().ok()); if var.is_none() && history.is_none() { // Expanding a non-existent variable. if !is_single { // Normal expansions of missing variables successfully expand to nothing. return ExpandResult::ok(); } else { // Expansion to single argument. // Replace the variable name and slice with VARIABLE_EXPAND_EMPTY. let mut res = instr[..varexp_char_idx].to_owned(); if res.as_char_slice().last() == Some(&VARIABLE_EXPAND_SINGLE) { res.push(VARIABLE_EXPAND_EMPTY); } res.push_utfstr(&instr[var_name_and_slice_stop..]); return expand_variables(res, out, varexp_char_idx, vars, errors); } } // Ok, we have a variable or a history. Let's expand it. // Start by respecting the sliced elements. assert!( var.is_some() || history.is_some(), "Should have variable or history here", ); let mut var_item_list = vec![]; if all_values { var_item_list = if let Some(ref history) = history { history.get_history() } else { var.as_ref().unwrap().as_list().to_vec() }; } else { // We have to respect the slice. if let Some(ref history) = history { // Ask history to map indexes to item strings. // Note this may have missing entries for out-of-bounds. let item_map = history.items_at_indexes(var_idx_list.clone()); for item_index in var_idx_list { if let Some(item) = item_map.get(&item_index) { var_item_list.push(item.clone()); } } } else { let all_var_items = var.as_ref().unwrap().as_list(); for item_index in var_idx_list { // Check that we are within array bounds. If not, skip the element. Note: // Negative indices (`echo $foo[-1]`) are already converted to positive ones // here, So tmp < 1 means it's definitely not in. // Note we are 1-based. if item_index >= 1 && item_index <= all_var_items.len() { var_item_list.push(all_var_items[item_index - 1].to_owned()); } } } } if is_single { // Quoted expansion. Here we expect the variable's delimiter. // Note history always has a space delimiter. let delimit = if history.is_some() { ' ' } else { var.as_ref().unwrap().get_delimiter() }; let mut res = instr[..varexp_char_idx].to_owned(); if !res.is_empty() { if res.as_char_slice().last() != Some(&VARIABLE_EXPAND_SINGLE) { res.push(INTERNAL_SEPARATOR); } else if var_item_list.is_empty() || var_item_list[0].is_empty() { // First expansion is empty, but we need to recursively expand. res.push(VARIABLE_EXPAND_EMPTY); } } // Append all entries in var_item_list, separated by the delimiter. res.push_utfstr(&join_strings(&var_item_list, delimit)); res.push_utfstr(&instr[var_name_and_slice_stop..]); return expand_variables(res, out, varexp_char_idx, vars, errors); } else { // Normal cartesian-product expansion. for item in var_item_list { if varexp_char_idx == 0 && var_name_and_slice_stop == instr.len() { if !out.add(item) { return append_overflow_error(errors, None); } } else { let mut new_in = instr[..varexp_char_idx].to_owned(); if !new_in.is_empty() { if new_in.as_char_slice().last() != Some(&VARIABLE_EXPAND) { new_in.push(INTERNAL_SEPARATOR); } else if item.is_empty() { new_in.push(VARIABLE_EXPAND_EMPTY); } } new_in.push_utfstr(&item); new_in.push_utfstr(&instr[var_name_and_slice_stop..]); let res = expand_variables(new_in, out, varexp_char_idx, vars, errors); if res.result != ExpandResultCode::ok { return res; } } } } ExpandResult::ok() } /// Perform brace expansion, placing the expanded strings into `out`. fn expand_braces( input: WString, flags: ExpandFlags, out: &mut CompletionReceiver, errors: &mut Option<&mut ParseErrorList>, ) -> ExpandResult { let mut syntax_error = false; let mut brace_count = 0; let mut brace_begin = None; let mut brace_end = None; let mut last_sep = None; // Locate the first non-nested brace pair. for (pos, c) in input.chars().enumerate() { match c { BRACE_BEGIN => { if brace_count == 0 { brace_begin = Some(pos); } brace_count += 1; } BRACE_END => { brace_count -= 1; #[allow(clippy::comparison_chain)] if brace_count < 0 { syntax_error = true; } else if brace_count == 0 { brace_end = Some(pos); } } BRACE_SEP => { if brace_count == 1 { last_sep = Some(pos); } } _ => { // we ignore all other characters here } } } if brace_count > 0 { if !flags.contains(ExpandFlags::FOR_COMPLETIONS) { syntax_error = true; } else { // The user hasn't typed an end brace yet; make one up and append it, then expand // that. let mut synth = WString::new(); if let Some(last_sep) = last_sep { synth.push_utfstr(&input[..brace_begin.unwrap() + 1]); synth.push_utfstr(&input[last_sep + 1..]); synth.push(BRACE_END); } else { synth.push_utfstr(&input); synth.push(BRACE_END); } // Note: this code looks very fishy, apparently it has never worked. return expand_braces(synth, ExpandFlags::FAIL_ON_CMDSUBST, out, errors); } } if syntax_error { append_syntax_error!(errors, SOURCE_LOCATION_UNKNOWN, "Mismatched braces"); return ExpandResult::make_error(STATUS_EXPAND_ERROR.unwrap()); } let Some(brace_begin) = brace_begin else { // No more brace expansions left; we can return the value as-is. if !out.add(input) { return append_overflow_error(errors, None); } return ExpandResult::ok(); }; let brace_end = brace_end.unwrap(); let length_preceding_braces = brace_begin; let length_following_braces = input.len() - brace_end - 1; let tot_len = length_preceding_braces + length_following_braces; let mut item_begin = brace_begin + 1; for (pos, c) in input.chars().enumerate().skip(brace_begin + 1) { if brace_count == 0 && (c == BRACE_SEP || pos == brace_end) { assert!(pos >= item_begin); let item_len = pos - item_begin; let item = input[item_begin..pos].to_owned(); let mut item = trim(item, Some(wstr::from_char_slice(&[BRACE_SPACE, '\0']))); for c in item.as_char_slice_mut() { if *c == BRACE_SPACE { *c = ' '; } } // `whole_item` is a whitespace- and brace-stripped member of a single pass of brace // expansion, e.g. in `{ alpha , b,{c, d }}`, `alpha`, `b`, and `c, d` will, in the // first round of expansion, each in turn be a `whole_item` (with recursive commas // replaced by special placeholders). // We recursively call `expand_braces` with each item until it's been fully expanded. let mut whole_item = WString::new(); whole_item.reserve(tot_len + item_len + 2); whole_item.push_utfstr(&input[..length_preceding_braces]); whole_item.push_utfstr(&item); whole_item.push_utfstr(&input[brace_end + 1..]); let _ = expand_braces(whole_item, flags, out, errors); item_begin = pos + 1; if pos == brace_end { break; } } if c == BRACE_BEGIN { brace_count += 1; } if c == BRACE_END { brace_count -= 1; } } ExpandResult::ok() } /// Expand a command substitution `input`, executing on `ctx`, and inserting the results into /// `out_list`, or any errors into `errors`. Return an expand result. pub fn expand_cmdsubst( input: WString, ctx: &OperationContext, out: &mut CompletionReceiver, errors: &mut Option<&mut ParseErrorList>, ) -> ExpandResult { let mut cursor = 0; let mut is_quoted = false; let mut has_dollar = false; let parens = match parse_util_locate_cmdsubst_range( &input, &mut cursor, false, Some(&mut is_quoted), Some(&mut has_dollar), ) { MaybeParentheses::Error => { append_syntax_error!(errors, SOURCE_LOCATION_UNKNOWN, "Mismatched parenthesis"); return ExpandResult::make_error(STATUS_EXPAND_ERROR.unwrap()); } MaybeParentheses::None => { if !out.add(input) { return append_overflow_error(errors, None); } return ExpandResult::ok(); } MaybeParentheses::CommandSubstitution(parens) => parens, }; let mut sub_res = vec![]; let job_group = ctx.job_group.clone(); let subshell_status = exec_subshell_for_expand( &input[parens.command()], ctx.parser(), job_group.as_ref(), &mut sub_res, ); if subshell_status != 0 { // TODO: Ad-hoc switch, how can we enumerate the possible errors more safely? let err = match subshell_status { _ if subshell_status == STATUS_READ_TOO_MUCH.unwrap() => { wgettext!("Too much data emitted by command substitution so it was discarded") } // TODO: STATUS_CMD_ERROR is overused and too generic. We shouldn't have to test things // to figure out what error to show after we've already been given an error code. _ if subshell_status == STATUS_CMD_ERROR.unwrap() => { if ctx.parser().is_eval_depth_exceeded() { wgettext!("Unable to evaluate string substitution") } else { wgettext!("Too many active file descriptors") } } _ if subshell_status == STATUS_CMD_UNKNOWN.unwrap() => { wgettext!("Unknown command") } _ if subshell_status == STATUS_ILLEGAL_CMD.unwrap() => { wgettext!("Commandname was invalid") } _ if subshell_status == STATUS_NOT_EXECUTABLE.unwrap() => { wgettext!("Command not executable") } _ if subshell_status == STATUS_INVALID_ARGS.unwrap() => { // TODO: Also overused // This is sent for: // invalid redirections or pipes (like `<&foo`), // invalid variables (invalid name or read-only) for for-loops, // switch $foo if $foo expands to more than one argument // time in a background job. wgettext!("Invalid arguments") } _ if subshell_status == STATUS_EXPAND_ERROR.unwrap() => { // Sent in `for $foo in ...` if $foo expands to more than one word wgettext!("Expansion error") } _ if subshell_status == STATUS_UNMATCHED_WILDCARD.unwrap() => { // Sent in `for $foo in ...` if $foo expands to more than one word wgettext!("Unmatched wildcard") } _ => { wgettext!("Unknown error while evaluating command substitution") } }; append_cmdsub_error_formatted!(errors, parens.start(), parens.end() - 1, err.to_owned()); return ExpandResult::make_error(subshell_status); } // Expand slices like (cat /var/words)[1] let mut tail_begin = parens.end(); if input.as_char_slice().get(tail_begin) == Some(&'[') { let mut slice_idx = vec![]; let slice_begin = tail_begin; let slice_end = match parse_slice(&input[slice_begin..], &mut slice_idx, sub_res.len()) { Ok(offset) => slice_begin + offset, Err((bad_pos, error)) => { match error { ParseSliceError::zero_index => { append_syntax_error!( errors, slice_begin + bad_pos, "array indices start at 1, not 0." ); } ParseSliceError::invalid_index => { append_syntax_error!(errors, slice_begin + bad_pos, "Invalid index value"); } } return ExpandResult::make_error(STATUS_EXPAND_ERROR.unwrap()); } }; let mut sub_res2 = vec![]; tail_begin = slice_end; for idx in slice_idx { if idx as usize > sub_res.len() || idx < 1 { continue; } // -1 to convert from 1-based slice index to 0-based vector index. sub_res2.push(sub_res[idx as usize - 1].to_owned()); } sub_res = sub_res2; } // Recursively call ourselves to expand any remaining command substitutions. The result of this // recursive call using the tail of the string is inserted into the tail_expand array list let mut tail_expand_recv = out.subreceiver(); let mut tail = input[tail_begin..].to_owned(); // A command substitution inside double quotes magically closes the quoted string. // Reopen the quotes just after the command substitution. if is_quoted { tail.insert(0, '"'); } let _ = expand_cmdsubst(tail, ctx, &mut tail_expand_recv, errors); // TODO: offset error locations let tail_expand = tail_expand_recv.take(); // Combine the result of the current command substitution with the result of the recursive tail // expansion. if is_quoted { // Awkwardly reconstruct the command output. let approx_size = sub_res.iter().map(|sub_item| sub_item.len() + 1).sum(); let mut sub_res_joined = WString::new(); sub_res_joined.reserve(approx_size); for line in sub_res { sub_res_joined.push_utfstr(&escape_string_for_double_quotes(&line)); sub_res_joined.push('\n'); } // Mimic POSIX shells by stripping all trailing newlines. if !sub_res_joined.is_empty() { let mut i = sub_res_joined.len(); while i > 0 && sub_res_joined.as_char_slice()[i - 1] == '\n' { i -= 1; } sub_res_joined.truncate(i); } // Instead of performing cartesian product expansion, we directly insert the command // substitution output into the current expansion results. for tail_item in tail_expand { let mut whole_item = WString::new(); whole_item.reserve( parens.start() + 1 + sub_res_joined.len() + 1 + tail_item.completion.len(), ); whole_item.push_utfstr(&input[..parens.start() - if has_dollar { 1 } else { 0 }]); whole_item.push(INTERNAL_SEPARATOR); whole_item.push_utfstr(&sub_res_joined); whole_item.push(INTERNAL_SEPARATOR); whole_item.push_utfstr(&tail_item.completion["\"".len()..]); if !out.add(whole_item) { return append_overflow_error(errors, None); } } return ExpandResult::ok(); } for sub_item in sub_res { let sub_item2 = escape_string(&sub_item, EscapeStringStyle::Script(EscapeFlags::COMMA)); for tail_item in &*tail_expand { let mut whole_item = WString::new(); whole_item .reserve(parens.start() + 1 + sub_item2.len() + 1 + tail_item.completion.len()); whole_item.push_utfstr(&input[..parens.start() - if has_dollar { 1 } else { 0 }]); whole_item.push(INTERNAL_SEPARATOR); whole_item.push_utfstr(&sub_item2); whole_item.push(INTERNAL_SEPARATOR); whole_item.push_utfstr(&tail_item.completion); if !out.add(whole_item) { return append_overflow_error(errors, None); } } } ExpandResult::ok() } // Given that input[0] is HOME_DIRECTORY or tilde (ugh), return the user's name. Return the empty // string if it is just a tilde. Also return by reference the index of the first character of the // remaining part of the string (e.g. the subsequent slash). fn get_home_directory_name<'a>(input: &'a wstr, out_tail_idx: &mut usize) -> &'a wstr { assert!([HOME_DIRECTORY, '~'].contains(&input.as_char_slice()[0])); // We get the position of the /, but we need to remove it as well. if let Some(pos) = input.chars().position(|c| c == '/') { *out_tail_idx = pos; &input[1..pos] } else { *out_tail_idx = input.len(); &input[1..] } } /// Attempts tilde expansion of the string specified, modifying it in place. fn expand_home_directory(input: &mut WString, vars: &dyn Environment) { let starts_with_tilde = input.as_char_slice().first() == Some(&HOME_DIRECTORY); *input = input.replace([HOME_DIRECTORY], L!("~")); if !starts_with_tilde { return; } let mut tail_idx = usize::MAX; let username = get_home_directory_name(input, &mut tail_idx); let mut home = None; if username.is_empty() { // Current users home directory. match vars.get_unless_empty(L!("HOME")) { None => { input.clear(); return; } Some(home_var) => { home = Some(home_var.as_string()); tail_idx = 1; } }; } else { // Some other user's home directory. let name_cstr = wcs2zstring(username); let mut userinfo: libc::passwd = unsafe { std::mem::zeroed() }; let mut result: *mut libc::passwd = std::ptr::null_mut(); let mut buf = [0 as libc::c_char; 8192]; let retval = unsafe { libc::getpwnam_r( name_cstr.as_ptr(), &mut userinfo, &mut buf[0], std::mem::size_of_val(&buf), &mut result, ) }; if retval == 0 && !result.is_null() { home = Some(charptr2wcstring(userinfo.pw_dir)); } } if let Some(home) = home { input.replace_range(..tail_idx, &normalize_path(&home, true)); } } /// Expand the %self escape. Note this can only come at the beginning of the string. fn expand_percent_self(input: &mut WString) { if input.as_char_slice().first() == Some(&PROCESS_EXPAND_SELF) { input.replace_range(0..1, &unsafe { libc::getpid() }.to_wstring()); } } /// Remove any internal separators. Also optionally convert wildcard characters to regular /// equivalents. This is done to support skip_wildcards. fn remove_internal_separator(s: &mut WString, conv: bool) { // Remove all instances of INTERNAL_SEPARATOR. s.retain(|c| c != INTERNAL_SEPARATOR); // If conv is true, replace all instances of ANY_STRING with '*', // ANY_STRING_RECURSIVE with '*'. if conv { for idx in s.as_char_slice_mut() { match *idx { ANY_CHAR => { *idx = '?'; } ANY_STRING | ANY_STRING_RECURSIVE => { *idx = '*'; } _ => { // we ignore all other characters } } } } } /// A type that knows how to perform expansions. struct Expander<'a, 'b, 'c> { /// Operation context for this expansion. ctx: &'c OperationContext<'b>, /// Flags to use during expansion. flags: ExpandFlags, /// List to receive any errors generated during expansion, or null to ignore errors. errors: &'c mut Option<&'a mut ParseErrorList>, } impl<'a, 'b, 'c> Expander<'a, 'b, 'c> { fn new( ctx: &'c OperationContext<'b>, flags: ExpandFlags, errors: &'c mut Option<&'a mut ParseErrorList>, ) -> Self { Self { ctx, flags, errors } } fn expand_string( input: WString, out_completions: &'a mut CompletionReceiver, flags: ExpandFlags, ctx: &'a OperationContext<'b>, mut errors: Option<&'a mut ParseErrorList>, ) -> ExpandResult { assert!( flags.contains(ExpandFlags::FAIL_ON_CMDSUBST) || ctx.has_parser(), "Must have a parser if not skipping command substitutions" ); // Early out. If we're not completing, and there's no magic in the input, we're done. if !flags.contains(ExpandFlags::FOR_COMPLETIONS) && expand_is_clean(&input) { if !out_completions.add(input) { return append_overflow_error(&mut errors, None); } return ExpandResult::ok(); } let mut expand = Expander::new(ctx, flags, &mut errors); // Our expansion stages. // An expansion stage is a member function pointer. // It accepts the input string (transferring ownership) and returns the list of output // completions by reference. It may return an error, which halts expansion. let stages = [ Expander::stage_cmdsubst, Expander::stage_variables, Expander::stage_braces, Expander::stage_home_and_self, Expander::stage_wildcards, ]; // Load up our single initial completion. let mut completions = vec![Completion::from_completion(input.clone())]; let mut total_result = ExpandResult::ok(); let mut output_storage = out_completions.subreceiver(); for stage in stages { for comp in completions { if expand.ctx.check_cancel() { total_result = ExpandResult::new(ExpandResultCode::cancel); break; } let this_result = (stage)(&mut expand, comp.completion, &mut output_storage); total_result = this_result; if total_result == ExpandResultCode::error { break; } } // Output becomes our next stage's input. completions = output_storage.take(); if total_result == ExpandResultCode::error { break; } } // This is a little tricky: if one wildcard failed to match but we still got output, it // means that a previous expansion resulted in multiple strings. For example: // set dirs ./a ./b // echo $dirs/*.txt // Here if ./a/*.txt matches and ./b/*.txt does not, then we don't want to report a failed // wildcard. So swallow failed-wildcard errors if we got any output. if total_result == ExpandResultCode::wildcard_no_match && !completions.is_empty() { total_result = ExpandResult::ok(); } if total_result == ExpandResultCode::ok { // Unexpand tildes if we want to preserve them (see #647). if flags.contains(ExpandFlags::PRESERVE_HOME_TILDES) { expand.unexpand_tildes(&input, &mut completions); } if !out_completions.extend(completions) { total_result = append_overflow_error(expand.errors, None); } } total_result } fn stage_cmdsubst(&mut self, input: WString, out: &mut CompletionReceiver) -> ExpandResult { if self.flags.contains(ExpandFlags::SKIP_CMDSUBST) { if !out.add(input) { return append_overflow_error(self.errors, None); } return ExpandResult::ok(); } if self.flags.contains(ExpandFlags::FAIL_ON_CMDSUBST) { let mut cursor = 0; match parse_util_locate_cmdsubst_range(&input, &mut cursor, true, None, None) { MaybeParentheses::Error => { return ExpandResult::make_error(STATUS_EXPAND_ERROR.unwrap()); } MaybeParentheses::None => { if !out.add(input) { return append_overflow_error(self.errors, None); } return ExpandResult::ok(); } MaybeParentheses::CommandSubstitution(parens) => { append_cmdsub_error!( self.errors, parens.start(), parens.end()-1, "command substitutions not allowed in command position. Try var=(your-cmd) $var ..." ); return ExpandResult::make_error(STATUS_EXPAND_ERROR.unwrap()); } } } else { assert!( self.ctx.has_parser(), "Must have a parser to expand command substitutions" ); expand_cmdsubst(input, self.ctx, out, self.errors) } } // We pass by value to match other stages. NOLINTNEXTLINE(performance-unnecessary-value-param) fn stage_variables(&mut self, input: WString, out: &mut CompletionReceiver) -> ExpandResult { // We accept incomplete strings here, since complete uses expand_string to expand incomplete // strings from the commandline. let mut next = unescape_string( &input, UnescapeStringStyle::Script(UnescapeFlags::SPECIAL | UnescapeFlags::INCOMPLETE), ) .unwrap_or_default(); if self.flags.contains(ExpandFlags::SKIP_VARIABLES) { for i in next.as_char_slice_mut() { if [VARIABLE_EXPAND, VARIABLE_EXPAND_SINGLE].contains(i) { *i = '$'; } } if !out.add(next) { return append_overflow_error(self.errors, None); } ExpandResult::ok() } else { let size = next.len(); expand_variables(next, out, size, self.ctx.vars(), self.errors) } } fn stage_braces(&mut self, input: WString, out: &mut CompletionReceiver) -> ExpandResult { expand_braces(input, self.flags, out, self.errors) } fn stage_home_and_self( &mut self, mut input: WString, out: &mut CompletionReceiver, ) -> ExpandResult { expand_home_directory(&mut input, self.ctx.vars()); if !feature_test(FeatureFlag::remove_percent_self) { expand_percent_self(&mut input); } if !out.add(input) { return append_overflow_error(self.errors, None); } ExpandResult::ok() } fn stage_wildcards( &mut self, mut path_to_expand: WString, out: &mut CompletionReceiver, ) -> ExpandResult { let mut result = ExpandResult::ok(); remove_internal_separator( &mut path_to_expand, self.flags.contains(ExpandFlags::SKIP_WILDCARDS), ); let has_wildcard = wildcard_has_internal(&path_to_expand); // e.g. ANY_STRING let for_completions = self.flags.contains(ExpandFlags::FOR_COMPLETIONS); let skip_wildcards = self.flags.contains(ExpandFlags::SKIP_WILDCARDS); if has_wildcard && self.flags.contains(ExpandFlags::EXECUTABLES_ONLY) { // don't do wildcard expansion for executables, see issue #785 } else if (for_completions && !skip_wildcards) || has_wildcard { // We either have a wildcard, or we don't have a wildcard but we're doing completion // expansion (so we want to get the completion of a file path). Note that if // skip_wildcards is set, we stomped wildcards in remove_internal_separator above, so // there actually aren't any. // // So we're going to treat this input as a file path. Compute the "working directories", // which may be CDPATH if the special flag is set. let working_dir = self.ctx.vars().get_pwd_slash(); let mut effective_working_dirs = vec![]; let for_cd = self.flags.contains(ExpandFlags::SPECIAL_FOR_CD); let for_command = self.flags.contains(ExpandFlags::SPECIAL_FOR_COMMAND); if !for_cd && !for_command { // Common case. effective_working_dirs.push(working_dir); } else { // Either special_for_command or special_for_cd. We can handle these // mostly the same. There's the following differences: // // 1. An empty CDPATH should be treated as '.', but an empty PATH should be left empty // (no commands can be found). Also, an empty element in either is treated as '.' for // consistency with POSIX shells. Note that we rely on the latter by having called // `munge_colon_delimited_array()` for these special env vars. Thus we do not // special-case them here. // // 2. PATH is only "one level," while CDPATH is multiple levels. That is, input like // 'foo/bar' should resolve against CDPATH, but not PATH. // // In either case, we ignore the path if we start with ./ or /. Also ignore it if we are // doing command completion and we contain a slash, per IEEE 1003.1, chapter 8 under // PATH. if path_to_expand.starts_with(L!("/")) || path_to_expand.starts_with(L!("./")) || path_to_expand.starts_with(L!("../")) || (for_command && path_to_expand.contains('/')) { effective_working_dirs.push(working_dir); } else { // Get the PATH/CDPATH and CWD. Perhaps these should be passed in. An empty CDPATH // implies just the current directory, while an empty PATH is left empty. let mut paths = self .ctx .vars() .get(if for_cd { L!("CDPATH") } else { L!("PATH") }) .map(|var| var.as_list().to_owned()) .unwrap_or_default(); // The current directory is always valid. paths.push(if for_cd { L!(".") } else { L!("") }.to_owned()); for next_path in paths { effective_working_dirs .push(path_apply_working_directory(&next_path, &working_dir)); } } } result = ExpandResult::new(ExpandResultCode::wildcard_no_match); let mut expanded_recv = out.subreceiver(); for effective_working_dir in effective_working_dirs { let expand_res = wildcard_expand_string( &path_to_expand, &effective_working_dir, self.flags, &*self.ctx.cancel_checker, &mut expanded_recv, ); match expand_res { WildcardResult::Match => result = ExpandResult::ok(), WildcardResult::NoMatch => (), WildcardResult::Overflow => return append_overflow_error(self.errors, None), WildcardResult::Cancel => return ExpandResult::new(ExpandResultCode::cancel), } } let mut expanded = expanded_recv.take(); expanded.sort_by(|a, b| wcsfilecmp_glob(&a.completion, &b.completion)); if !out.extend(expanded) { result = ExpandResult::new(ExpandResultCode::error); } } else { // Can't fully justify this check. I think it's that SKIP_WILDCARDS is used when completing // to mean don't do file expansions, so if we're not doing file expansions, just drop this // completion on the floor. #[allow(clippy::collapsible_if)] if !self.flags.contains(ExpandFlags::FOR_COMPLETIONS) { if !out.add(path_to_expand) { return append_overflow_error(self.errors, None); } } } result } // Given an original input string, if it starts with a tilde, "unexpand" the expanded home // directory. Note this may be just a tilde or a user name like ~foo/. fn unexpand_tildes(&self, input: &wstr, completions: &mut CompletionList) { // If input begins with tilde, then try to replace the corresponding string in each completion // with the tilde. If it does not, there's nothing to do. if input.as_char_slice().first() != Some(&'~') { return; } // This is a subtle kludge. We need to decide whether to unexpand tildes for all // completions, or only those which replace their tokens. The problem is that we're sloppy // about setting the COMPLETE_REPLACES_TOKEN flag, except when we're completing in the // wildcard stage, because no other clients of string expansion care. Example: // HOME=/foo // mkdir ~/foo # makes /foo/foo // cd ~/ // Here we are likely to get a completion 'foo' which may match $HOME, but it extends its token // instead of replacing it, so we don't modify it (it will just be appended to the original ~/). // // However if we are not completing, just expanding, then expansion just produces the full paths // so we should unconditionally unexpand tildes. let only_replacers = self.flags.contains(ExpandFlags::FOR_COMPLETIONS); // Helper to decide whether to process a completion. let should_process = |c: &Completion| !only_replacers || c.replaces_token(); // Early out if none qualify. if !completions.iter().any(should_process) { return; } // Get the username_with_tilde (like ~bert) and expand it into a home directory. let mut tail_idx = usize::MAX; let username_with_tilde = WString::from_str("~") + get_home_directory_name(input, &mut tail_idx); let mut home = username_with_tilde.clone(); expand_tilde(&mut home, self.ctx.vars()); // Now for each completion that starts with home, replace it with the username_with_tilde. for comp in completions { if should_process(comp) && comp.completion.starts_with(&home) { comp.completion .replace_range(..home.len(), &username_with_tilde); // And mark that our tilde is literal, so it doesn't try to escape it. comp.flags |= CompleteFlags::DONT_ESCAPE_TILDES; } } } } #[derive(Copy, Clone, Debug, Eq, PartialEq)] pub enum ExpandResultCode { /// There was an error, for example, unmatched braces. error, /// Expansion succeeded. ok, /// Expansion was cancelled (e.g. control-C). cancel, /// Expansion succeeded, but a wildcard in the string matched no files, /// so the output is empty. wildcard_no_match, } /// These are the possible return values for expand_string. #[must_use] #[derive(Debug)] pub struct ExpandResult { /// The result of expansion. pub result: ExpandResultCode, /// If expansion resulted in an error, this is an appropriate value with which to populate /// $status. // todo!("should be c_int?"); pub status: i32, }