fish-shell/src/tokenizer.cpp
Aaron Gyes d837eee09d remove some wcstring -> wchar_t* -> wcstring conversions
Mostly related to usage _(L"foo"), keeping in mind the _
macro does a wcstring().c_str() already.

And a smattering of other trivial micro-optimizations certain
to not help tangibly.
2019-03-14 15:21:08 -07:00

760 lines
27 KiB
C++

// A specialized tokenizer for tokenizing the fish language. In the future, the tokenizer should be
// extended to support marks, tokenizing multiple strings and disposing of unused string segments.
#include "config.h" // IWYU pragma: keep
#include <fcntl.h>
#include <limits.h>
#include <unistd.h>
#include <cwchar>
#include <wctype.h>
#include <string>
#include <type_traits>
#include "common.h"
#include "fallback.h" // IWYU pragma: keep
#include "future_feature_flags.h"
#include "tokenizer.h"
#include "wutil.h" // IWYU pragma: keep
// _(s) is already wgettext(s).c_str(), so let's not convert back to wcstring
const wchar_t * tokenizer_get_error_message(tokenizer_error_t err) {
switch (err) {
case tokenizer_error_t::none:
return L"";
case tokenizer_error_t::unterminated_quote:
return _(L"Unexpected end of string, quotes are not balanced");
case tokenizer_error_t::unterminated_subshell:
return _(L"Unexpected end of string, expecting ')'");
case tokenizer_error_t::unterminated_slice:
return _(L"Unexpected end of string, square brackets do not match");
case tokenizer_error_t::unterminated_escape:
return _(L"Unexpected end of string, incomplete escape sequence");
case tokenizer_error_t::invalid_redirect:
return _(L"Invalid input/output redirection");
case tokenizer_error_t::invalid_pipe:
return _(L"Cannot use stdin (fd 0) as pipe output");
case tokenizer_error_t::closing_unopened_subshell:
return _(L"Unexpected ')' for unopened parenthesis");
case tokenizer_error_t::illegal_slice:
return _(L"Unexpected '[' at this location");
case tokenizer_error_t::closing_unopened_brace:
return _(L"Unexpected '}' for unopened brace expansion");
case tokenizer_error_t::unterminated_brace:
return _(L"Unexpected end of string, incomplete parameter expansion");
case tokenizer_error_t::expected_pclose_found_bclose:
return _(L"Unexpected '}' found, expecting ')'");
case tokenizer_error_t::expected_bclose_found_pclose:
return _(L"Unexpected ')' found, expecting '}'");
}
assert(0 && "Unexpected tokenizer error");
return nullptr;
}
// Whether carets redirect stderr.
static bool caret_redirs() { return !feature_test(features_t::stderr_nocaret); }
/// Return an error token and mark that we no longer have a next token.
tok_t tokenizer_t::call_error(tokenizer_error_t error_type, const wchar_t *token_start,
const wchar_t *error_loc) {
assert(error_type != tokenizer_error_t::none && "tokenizer_error_t::none passed to call_error");
assert(error_loc >= token_start && "Invalid error location");
assert(this->buff >= token_start && "Invalid buff location");
this->has_next = false;
tok_t result;
result.type = TOK_ERROR;
result.error = error_type;
result.offset = token_start - this->start;
result.length = this->buff - token_start;
result.error_offset = error_loc - token_start;
return result;
}
tokenizer_t::tokenizer_t(const wchar_t *start, tok_flags_t flags) : buff(start), start(start) {
assert(start != nullptr && "Invalid start");
this->accept_unfinished = static_cast<bool>(flags & TOK_ACCEPT_UNFINISHED);
this->show_comments = static_cast<bool>(flags & TOK_SHOW_COMMENTS);
this->show_blank_lines = static_cast<bool>(flags & TOK_SHOW_BLANK_LINES);
}
bool tokenizer_t::next(struct tok_t *result) {
assert(result != NULL);
maybe_t<tok_t> tok = this->tok_next();
if (!tok) {
return false;
}
*result = std::move(*tok);
return true;
}
/// Tests if this character can be a part of a string. The redirect ^ is allowed unless it's the
/// first character. Hash (#) starts a comment if it's the first character in a token; otherwise it
/// is considered a string character. See issue #953.
static bool tok_is_string_character(wchar_t c, bool is_first) {
switch (c) {
case L'\0':
case L' ':
case L'\n':
case L'|':
case L'\t':
case L';':
case L'\r':
case L'<':
case L'>':
case L'&': {
// Unconditional separators.
return false;
}
case L'^': {
// Conditional separator.
return !caret_redirs() || !is_first;
}
default: { return true; }
}
}
/// Quick test to catch the most common 'non-magical' characters, makes read_string slightly faster
/// by adding a fast path for the most common characters. This is obviously not a suitable
/// replacement for iswalpha.
static inline int myal(wchar_t c) { return (c >= L'a' && c <= L'z') || (c >= L'A' && c <= L'Z'); }
namespace tok_modes {
enum {
regular_text = 0, // regular text
subshell = 1 << 0, // inside of subshell parentheses
array_brackets = 1 << 1, // inside of array brackets
curly_braces = 1 << 2,
char_escape = 1 << 3,
};
}
using tok_mode_t = uint32_t;
/// Read the next token as a string.
tok_t tokenizer_t::read_string() {
tok_mode_t mode{tok_modes::regular_text};
std::vector<int> paran_offsets;
std::vector<int> brace_offsets;
std::vector<char> expecting;
int slice_offset = 0;
const wchar_t *const buff_start = this->buff;
bool is_first = true;
while (true) {
wchar_t c = *this->buff;
#if false
wcstring msg = L"Handling 0x%x (%lc)";
tok_mode mode_begin = mode;
#endif
if (c == L'\0') {
break;
}
// Make sure this character isn't being escaped before anything else
if ((mode & tok_modes::char_escape) == tok_modes::char_escape) {
mode &= ~(tok_modes::char_escape);
// and do nothing more
} else if (myal(c)) {
// Early exit optimization in case the character is just a letter,
// which has no special meaning to the tokenizer, i.e. the same mode continues.
}
// Now proceed with the evaluation of the token, first checking to see if the token
// has been explicitly ignored (escaped).
else if (c == L'\\') {
mode |= tok_modes::char_escape;
} else if (c == L'(') {
paran_offsets.push_back(this->buff - this->start);
expecting.push_back(L')');
mode |= tok_modes::subshell;
} else if (c == L'{') {
brace_offsets.push_back(this->buff - this->start);
expecting.push_back(L'}');
mode |= tok_modes::curly_braces;
} else if (c == L')') {
if (expecting.size() > 0 && expecting.back() == L'}') {
return this->call_error(tokenizer_error_t::expected_bclose_found_pclose,
this->start, this->buff);
}
switch (paran_offsets.size()) {
case 0:
return this->call_error(tokenizer_error_t::closing_unopened_subshell,
this->start, this->buff);
case 1:
mode &= ~(tok_modes::subshell);
default:
paran_offsets.pop_back();
}
expecting.pop_back();
} else if (c == L'}') {
if (expecting.size() > 0 && expecting.back() == L')') {
return this->call_error(tokenizer_error_t::expected_pclose_found_bclose,
this->start, this->buff);
}
switch (brace_offsets.size()) {
case 0:
return this->call_error(tokenizer_error_t::closing_unopened_brace, this->start,
this->buff);
case 1:
mode &= ~(tok_modes::curly_braces);
default:
brace_offsets.pop_back();
}
expecting.pop_back();
} else if (c == L'[') {
if (this->buff != buff_start) {
mode |= tok_modes::array_brackets;
slice_offset = this->buff - this->start;
} else {
// This is actually allowed so the test operator `[` can be used as the head of a
// command
}
}
// Only exit bracket mode if we are in bracket mode.
// Reason: `]` can be a parameter, e.g. last parameter to `[` test alias.
// e.g. echo $argv[([ $x -eq $y ])] # must not end bracket mode on first bracket
else if (c == L']' && ((mode & tok_modes::array_brackets) == tok_modes::array_brackets)) {
mode &= ~(tok_modes::array_brackets);
} else if (c == L'\'' || c == L'"') {
const wchar_t *end = quote_end(this->buff);
if (end) {
this->buff = end;
} else {
const wchar_t *error_loc = this->buff;
this->buff += std::wcslen(this->buff);
if ((!this->accept_unfinished)) {
return this->call_error(tokenizer_error_t::unterminated_quote, buff_start,
error_loc);
}
break;
}
} else if (mode == tok_modes::regular_text && !tok_is_string_character(c, is_first)) {
break;
}
#if false
if (mode != mode_begin) {
msg.append(L": mode 0x%x -> 0x%x\n");
} else {
msg.push_back(L'\n');
}
debug(0, msg.c_str(), c, c, int(mode_begin), int(mode));
#endif
this->buff++;
is_first = false;
}
if ((!this->accept_unfinished) && (mode != tok_modes::regular_text)) {
tok_t error;
if ((mode & tok_modes::char_escape) == tok_modes::char_escape) {
error = this->call_error(tokenizer_error_t::unterminated_escape, buff_start,
this->buff - 1);
} else if ((mode & tok_modes::array_brackets) == tok_modes::array_brackets) {
error = this->call_error(tokenizer_error_t::unterminated_slice, buff_start,
this->start + slice_offset);
} else if ((mode & tok_modes::subshell) == tok_modes::subshell) {
assert(paran_offsets.size() > 0);
size_t offset_of_open_paran = paran_offsets.back();
error = this->call_error(tokenizer_error_t::unterminated_subshell, buff_start,
this->start + offset_of_open_paran);
} else if ((mode & tok_modes::curly_braces) == tok_modes::curly_braces) {
assert(brace_offsets.size() > 0);
size_t offset_of_open_brace = brace_offsets.back();
error = this->call_error(tokenizer_error_t::unterminated_brace, buff_start,
this->start + offset_of_open_brace);
}
return error;
}
tok_t result;
result.type = TOK_STRING;
result.offset = buff_start - this->start;
result.length = this->buff - buff_start;
return result;
}
// Reads a redirection or an "fd pipe" (like 2>|) from a string.
// Returns the parsed pipe or redirection, or none() on error.
struct parsed_redir_or_pipe_t {
// Number of characters consumed.
size_t consumed{0};
// The token type, always either TOK_PIPE or TOK_REDIRECT.
token_type type{TOK_REDIRECT};
// The redirection mode if the type is TOK_REDIRECT.
redirection_type_t redirection_mode{redirection_type_t::overwrite};
// The redirected fd, or -1 on overflow.
int fd{0};
};
static maybe_t<parsed_redir_or_pipe_t> read_redirection_or_fd_pipe(const wchar_t *buff) {
bool errored = false;
parsed_redir_or_pipe_t result;
size_t idx = 0;
// Determine the fd. This may be specified as a prefix like '2>...' or it may be implicit like
// '>' or '^'. Try parsing out a number; if we did not get any digits then infer it from the
// first character. Watch out for overflow.
long long big_fd = 0;
for (; iswdigit(buff[idx]); idx++) {
// Note that it's important we consume all the digits here, even if it overflows.
if (big_fd <= INT_MAX) big_fd = big_fd * 10 + (buff[idx] - L'0');
}
result.fd = (big_fd > INT_MAX ? -1 : static_cast<int>(big_fd));
if (idx == 0) {
// We did not find a leading digit, so there's no explicit fd. Infer it from the type.
switch (buff[idx]) {
case L'>': {
result.fd = STDOUT_FILENO;
break;
}
case L'<': {
result.fd = STDIN_FILENO;
break;
}
case L'^': {
if (caret_redirs()) {
result.fd = STDERR_FILENO;
} else {
errored = true;
}
break;
}
default: {
errored = true;
break;
}
}
}
// Either way we should have ended on the redirection character itself like '>'.
// Don't allow an fd with a caret redirection - see #1873
wchar_t redirect_char = buff[idx++]; // note increment of idx
if (redirect_char == L'>' || (redirect_char == L'^' && idx == 1 && caret_redirs())) {
result.redirection_mode = redirection_type_t::overwrite;
if (buff[idx] == redirect_char) {
// Doubled up like ^^ or >>. That means append.
result.redirection_mode = redirection_type_t::append;
idx++;
}
} else if (redirect_char == L'<') {
result.redirection_mode = redirection_type_t::input;
} else {
// Something else.
errored = true;
}
// Bail on error.
if (errored) {
return none();
}
// Optional characters like & or ?, or the pipe char |.
wchar_t opt_char = buff[idx];
if (opt_char == L'&') {
result.redirection_mode = redirection_type_t::fd;
idx++;
} else if (opt_char == L'?') {
result.redirection_mode = redirection_type_t::noclob;
idx++;
} else if (opt_char == L'|') {
// So the string looked like '2>|'. This is not a redirection - it's a pipe! That gets
// handled elsewhere.
result.type = TOK_PIPE;
idx++;
}
result.consumed = idx;
return result;
}
maybe_t<redirection_type_t> redirection_type_for_string(const wcstring &str, int *out_fd) {
auto v = read_redirection_or_fd_pipe(str.c_str());
// Redirections only, no pipes.
if (!v || v->type != TOK_REDIRECT || v->fd < 0) return none();
if (out_fd) *out_fd = v->fd;
return v->redirection_mode;
}
int fd_redirected_by_pipe(const wcstring &str) {
// Hack for the common case.
if (str == L"|") {
return STDOUT_FILENO;
}
auto v = read_redirection_or_fd_pipe(str.c_str());
return (v && v->type == TOK_PIPE) ? v->fd : -1;
}
int oflags_for_redirection_type(redirection_type_t type) {
switch (type) {
case redirection_type_t::append: {
return O_CREAT | O_APPEND | O_WRONLY;
}
case redirection_type_t::overwrite: {
return O_CREAT | O_WRONLY | O_TRUNC;
}
case redirection_type_t::noclob: {
return O_CREAT | O_EXCL | O_WRONLY;
}
case redirection_type_t::input: {
return O_RDONLY;
}
case redirection_type_t::fd:
default: {
return -1;
}
}
}
/// Test if a character is whitespace. Differs from iswspace in that it does not consider a newline
/// to be whitespace.
static bool iswspace_not_nl(wchar_t c) {
switch (c) {
case L' ':
case L'\t':
case L'\r':
return true;
case L'\n':
return false;
default:
return iswspace(c);
}
}
maybe_t<tok_t> tokenizer_t::tok_next() {
if (!this->has_next) {
return none();
}
// Consume non-newline whitespace. If we get an escaped newline, mark it and continue past it.
bool preceding_escaped_nl = false;
for (;;) {
if (this->buff[0] == L'\\' && this->buff[1] == L'\n') {
this->buff += 2;
this->continue_line_after_comment = true;
preceding_escaped_nl = true;
} else if (iswspace_not_nl(this->buff[0])) {
this->buff++;
} else {
break;
}
}
while (*this->buff == L'#') {
// We have a comment, walk over the comment.
const wchar_t *comment_start = this->buff;
while (this->buff[0] != L'\n' && this->buff[0] != L'\0') this->buff++;
size_t comment_len = this->buff - comment_start;
// If we are going to continue after the comment, skip any trailing newline.
if (this->buff[0] == L'\n' && this->continue_line_after_comment) this->buff++;
// Maybe return the comment.
if (this->show_comments) {
tok_t result;
result.type = TOK_COMMENT;
result.offset = comment_start - this->start;
result.length = comment_len;
result.preceding_escaped_nl = preceding_escaped_nl;
return result;
}
while (iswspace_not_nl(this->buff[0])) this->buff++;
}
// We made it past the comments and ate any trailing newlines we wanted to ignore.
this->continue_line_after_comment = false;
size_t start_pos = this->buff - this->start;
tok_t result;
result.offset = start_pos;
switch (*this->buff) {
case L'\0': {
this->has_next = false;
return none();
}
case L'\r': // carriage-return
case L'\n': // newline
case L';': {
result.type = TOK_END;
result.length = 1;
this->buff++;
// Hack: when we get a newline, swallow as many as we can. This compresses multiple
// subsequent newlines into a single one.
if (!this->show_blank_lines) {
while (*this->buff == L'\n' || *this->buff == 13 /* CR */ || *this->buff == ' ' ||
*this->buff == '\t') {
this->buff++;
}
}
break;
}
case L'&': {
if (this->buff[1] == L'&') {
result.type = TOK_ANDAND;
result.length = 2;
this->buff += 2;
} else {
result.type = TOK_BACKGROUND;
result.length = 1;
this->buff++;
}
break;
}
case L'|': {
if (this->buff[1] == L'|') {
result.type = TOK_OROR;
result.length = 2;
this->buff += 2;
} else {
result.type = TOK_PIPE;
result.redirected_fd = 1;
result.length = 1;
this->buff++;
}
break;
}
case L'>':
case L'<': {
// There's some duplication with the code in the default case below. The key difference
// here is that we must never parse these as a string; a failed redirection is an error!
auto redir_or_pipe = read_redirection_or_fd_pipe(this->buff);
if (!redir_or_pipe || redir_or_pipe->fd < 0) {
return this->call_error(tokenizer_error_t::invalid_redirect, this->buff,
this->buff);
}
result.type = redir_or_pipe->type;
result.redirected_fd = redir_or_pipe->fd;
result.length = redir_or_pipe->consumed;
this->buff += redir_or_pipe->consumed;
break;
}
default: {
// Maybe a redirection like '2>&1', maybe a pipe like 2>|, maybe just a string.
const wchar_t *error_location = this->buff;
maybe_t<parsed_redir_or_pipe_t> redir_or_pipe;
if (iswdigit(*this->buff) || (*this->buff == L'^' && caret_redirs())) {
redir_or_pipe = read_redirection_or_fd_pipe(this->buff);
}
if (redir_or_pipe && redir_or_pipe->consumed > 0) {
// It looks like a redirection or a pipe. But we don't support piping fd 0. Note
// that fd 0 may be -1, indicating overflow; but we don't treat that as a tokenizer
// error.
if (redir_or_pipe->type == TOK_PIPE && redir_or_pipe->fd == 0) {
return this->call_error(tokenizer_error_t::invalid_pipe, error_location,
error_location);
}
result.type = redir_or_pipe->type;
result.redirected_fd = redir_or_pipe->fd;
result.length = redir_or_pipe->consumed;
this->buff += redir_or_pipe->consumed;
} else {
// Not a redirection or pipe, so just a string.
result = this->read_string();
}
break;
}
}
result.preceding_escaped_nl = preceding_escaped_nl;
return result;
}
wcstring tok_first(const wcstring &str) {
tokenizer_t t(str.c_str(), 0);
tok_t token;
if (t.next(&token) && token.type == TOK_STRING) {
return t.text_of(token);
}
return {};
}
bool move_word_state_machine_t::consume_char_punctuation(wchar_t c) {
enum { s_always_one = 0, s_rest, s_whitespace_rest, s_whitespace, s_alphanumeric, s_end };
bool consumed = false;
while (state != s_end && !consumed) {
switch (state) {
case s_always_one: {
// Always consume the first character.
consumed = true;
if (iswspace(c)) {
state = s_whitespace;
} else {
// Don't allow switching type (ws->nonws) after non-whitespace.
state = s_rest;
}
break;
}
case s_rest: {
if (iswspace(c)) {
// Consume only trailing whitespace.
state = s_whitespace_rest;
} else if (iswalnum(c)) {
// Consume only alnums.
state = s_alphanumeric;
} else {
consumed = false;
state = s_end;
}
break;
}
case s_whitespace_rest:
case s_whitespace: {
// "whitespace" consumes whitespace and switches to alnums,
// "whitespace_rest" only consumes whitespace.
if (iswspace(c)) {
// Consumed whitespace.
consumed = true;
} else {
state = state == s_whitespace ? s_alphanumeric : s_end;
}
break;
}
case s_alphanumeric: {
if (iswalnum(c)) {
consumed = true; // consumed alphanumeric
} else {
state = s_end;
}
break;
}
case s_end:
default: { break; }
}
}
return consumed;
}
bool move_word_state_machine_t::is_path_component_character(wchar_t c) {
// Always treat separators as first. All this does is ensure that we treat ^ as a string
// character instead of as stderr redirection, which I hypothesize is usually what is desired.
return tok_is_string_character(c, true) && !std::wcschr(L"/={,}'\"", c);
}
bool move_word_state_machine_t::consume_char_path_components(wchar_t c) {
enum {
s_initial_punctuation,
s_whitespace,
s_separator,
s_slash,
s_path_component_characters,
s_end
};
// std::fwprintf(stdout, L"state %d, consume '%lc'\n", state, c);
bool consumed = false;
while (state != s_end && !consumed) {
switch (state) {
case s_initial_punctuation: {
if (!is_path_component_character(c)) {
consumed = true;
}
state = s_whitespace;
break;
}
case s_whitespace: {
if (iswspace(c)) {
consumed = true; // consumed whitespace
} else if (c == L'/' || is_path_component_character(c)) {
state = s_slash; // path component
} else {
state = s_separator; // path separator
}
break;
}
case s_separator: {
if (!iswspace(c) && !is_path_component_character(c)) {
consumed = true; // consumed separator
} else {
state = s_end;
}
break;
}
case s_slash: {
if (c == L'/') {
consumed = true; // consumed slash
} else {
state = s_path_component_characters;
}
break;
}
case s_path_component_characters: {
if (is_path_component_character(c)) {
consumed = true; // consumed string character except slash
} else {
state = s_end;
}
break;
}
case s_end:
default: { break; }
}
}
return consumed;
}
bool move_word_state_machine_t::consume_char_whitespace(wchar_t c) {
enum { s_always_one = 0, s_blank, s_graph, s_end };
bool consumed = false;
while (state != s_end && !consumed) {
switch (state) {
case s_always_one: {
consumed = true; // always consume the first character
state = s_blank;
break;
}
case s_blank: {
if (iswblank(c)) {
consumed = true; // consumed whitespace
} else {
state = s_graph;
}
break;
}
case s_graph: {
if (iswgraph(c)) {
consumed = true; // consumed printable non-space
} else {
state = s_end;
}
break;
}
case s_end:
default: { break; }
}
}
return consumed;
}
bool move_word_state_machine_t::consume_char(wchar_t c) {
switch (style) {
case move_word_style_punctuation: {
return consume_char_punctuation(c);
}
case move_word_style_path_components: {
return consume_char_path_components(c);
}
case move_word_style_whitespace: {
return consume_char_whitespace(c);
}
}
DIE("should not reach this statement"); // silence some compiler errors about not returning
}
move_word_state_machine_t::move_word_state_machine_t(move_word_style_t syl)
: state(0), style(syl) {}
void move_word_state_machine_t::reset() { state = 0; }