fish-shell/src/tokenizer.cpp
ridiculousfish e34a8da5d7 Correct the positioning of the error caret
When an error occurs midway through a token, like abc(def,
make the caret point at the location of the error (i.e. the paren)
instead of at the beginning of the token.
2015-08-10 18:31:20 -07:00

945 lines
26 KiB
C++

/** \file tokenizer.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 <wchar.h>
#include <wctype.h>
#include <unistd.h>
#include <fcntl.h>
#include <assert.h>
#include <string>
#include "fallback.h" // IWYU pragma: keep
#include "common.h"
#include "wutil.h" // IWYU pragma: keep - needed for wgettext
#include "tokenizer.h"
/* Wow what a hack */
#define TOK_CALL_ERROR(t, e, x, where) do { (t)->call_error((e), where, (t)->squash_errors ? L"" : (x)); } while (0)
/**
Error string for unexpected end of string
*/
#define QUOTE_ERROR _( L"Unexpected end of string, quotes are not balanced" )
/**
Error string for mismatched parenthesis
*/
#define PARAN_ERROR _( L"Unexpected end of string, parenthesis do not match" )
/**
Error string for mismatched square brackets
*/
#define SQUARE_BRACKET_ERROR _( L"Unexpected end of string, square brackets do not match" )
/**
Error string for unterminated escape (backslash without continuation)
*/
#define UNTERMINATED_ESCAPE_ERROR _( L"Unexpected end of string, incomplete escape sequence" )
/**
Error string for invalid redirections
*/
#define REDIRECT_ERROR _( L"Invalid input/output redirection" )
/**
Error string for when trying to pipe from fd 0
*/
#define PIPE_ERROR _( L"Cannot use stdin (fd 0) as pipe output" )
/**
Set the latest tokens string to be the specified error message
*/
void tokenizer_t::call_error(enum tokenizer_error error_type, const wchar_t *where, const wchar_t *error_message)
{
this->last_type = TOK_ERROR;
this->error = error_type;
this->global_error_offset = where ? where - this->orig_buff : 0;
this->last_token = error_message;
}
tokenizer_t::tokenizer_t(const wchar_t *b, tok_flags_t flags) : buff(b), orig_buff(b), last_type(TOK_NONE), last_pos(0), has_next(false), accept_unfinished(false), show_comments(false), show_blank_lines(false), error(TOK_ERROR_NONE), global_error_offset(-1), squash_errors(false), continue_line_after_comment(false)
{
assert(b != NULL);
this->accept_unfinished = !!(flags & TOK_ACCEPT_UNFINISHED);
this->show_comments = !!(flags & TOK_SHOW_COMMENTS);
this->squash_errors = !!(flags & TOK_SQUASH_ERRORS);
this->show_blank_lines = !!(flags & TOK_SHOW_BLANK_LINES);
this->has_next = (*b != L'\0');
this->tok_next();
}
bool tokenizer_t::next(struct tok_t *result)
{
assert(result != NULL);
if (! this->has_next)
{
return false;
}
const size_t current_pos = this->buff - this->orig_buff;
result->text = this->last_token;
result->type = this->last_type;
result->offset = this->last_pos;
result->error = this->last_type == TOK_ERROR ? this->error : TOK_ERROR_NONE;
assert(this->buff >= this->orig_buff);
/* Compute error offset */
result->error_offset = 0;
if (this->last_type == TOK_ERROR && this->global_error_offset >= this->last_pos && this->global_error_offset < current_pos)
{
result->error_offset = this->global_error_offset - this->last_pos;
}
assert(this->buff >= this->orig_buff);
result->length = current_pos >= this->last_pos ? current_pos - this->last_pos : 0;
this->tok_next();
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 #953.
*/
static bool tok_is_string_character(wchar_t c, bool is_first)
{
switch (c)
{
/* Unconditional separators */
case L'\0':
case L' ':
case L'\n':
case L'|':
case L'\t':
case L';':
case L'\r':
case L'<':
case L'>':
case L'&':
return false;
/* Conditional separator */
case L'^':
return ! 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 int myal(wchar_t c)
{
return (c>=L'a' && c<=L'z') || (c>=L'A'&&c<=L'Z');
}
/**
Read the next token as a string
*/
void tokenizer_t::read_string()
{
long len;
int do_loop=1;
size_t paran_count=0;
// up to 96 open parens, before we give up on good error reporting
const size_t paran_offsets_max = 96;
size_t paran_offsets[paran_offsets_max];
const wchar_t * const start = this->buff;
bool is_first = true;
enum tok_mode_t
{
mode_regular_text = 0, // regular text
mode_subshell = 1, // inside of subshell
mode_array_brackets = 2, // inside of array brackets
mode_array_brackets_and_subshell = 3 // inside of array brackets and subshell, like in '$foo[(ech'
} mode = mode_regular_text;
while (1)
{
if (!myal(*this->buff))
{
if (*this->buff == L'\\')
{
const wchar_t *error_location = this->buff;
this->buff++;
if (*this->buff == L'\0')
{
if ((!this->accept_unfinished))
{
TOK_CALL_ERROR(this, TOK_UNTERMINATED_ESCAPE, UNTERMINATED_ESCAPE_ERROR, error_location);
return;
}
else
{
/* Since we are about to increment tok->buff, decrement it first so the increment doesn't go past the end of the buffer. https://github.com/fish-shell/fish-shell/issues/389 */
this->buff--;
do_loop = 0;
}
}
this->buff++;
continue;
}
switch (mode)
{
case mode_regular_text:
{
switch (*this->buff)
{
case L'(':
{
paran_count=1;
paran_offsets[0] = this->buff - this->orig_buff;
mode = mode_subshell;
break;
}
case L'[':
{
if (this->buff != start)
mode = mode_array_brackets;
break;
}
case L'\'':
case L'"':
{
const wchar_t *end = quote_end(this->buff);
if (end)
{
this->buff=end;
}
else
{
const wchar_t *error_loc = this->buff;
this->buff += wcslen(this->buff);
if (! this->accept_unfinished)
{
TOK_CALL_ERROR(this, TOK_UNTERMINATED_QUOTE, QUOTE_ERROR, error_loc);
return;
}
do_loop = 0;
}
break;
}
default:
{
if (! tok_is_string_character(*(this->buff), is_first))
{
do_loop=0;
}
}
}
break;
}
case mode_array_brackets_and_subshell:
case mode_subshell:
{
switch (*this->buff)
{
case L'\'':
case L'\"':
{
const wchar_t *end = quote_end(this->buff);
if (end)
{
this->buff = end;
}
else
{
const wchar_t *error_loc = this->buff;
this->buff += wcslen(this->buff);
if ((!this->accept_unfinished))
{
TOK_CALL_ERROR(this, TOK_UNTERMINATED_QUOTE, QUOTE_ERROR, error_loc);
return;
}
do_loop = 0;
}
break;
}
case L'(':
if (paran_count < paran_offsets_max)
{
paran_offsets[paran_count] = this->buff - this->orig_buff;
}
paran_count++;
break;
case L')':
assert(paran_count > 0);
paran_count--;
if (paran_count == 0)
{
mode = (mode == mode_array_brackets_and_subshell ? mode_array_brackets : mode_regular_text);
}
break;
case L'\0':
do_loop = 0;
break;
}
break;
}
case mode_array_brackets:
{
switch (*this->buff)
{
case L'(':
paran_count=1;
paran_offsets[0] = this->buff - this->orig_buff;
mode = mode_array_brackets_and_subshell;
break;
case L']':
mode = mode_regular_text;
break;
case L'\0':
do_loop = 0;
break;
}
break;
}
}
}
if (!do_loop)
break;
this->buff++;
is_first = false;
}
if ((!this->accept_unfinished) && (mode != mode_regular_text))
{
switch (mode)
{
case mode_subshell:
{
// Determine the innermost opening paran offset by interrogating paran_offsets
assert(paran_count > 0);
size_t offset_of_open_paran = 0;
if (paran_count <= paran_offsets_max)
{
offset_of_open_paran = paran_offsets[paran_count - 1];
}
TOK_CALL_ERROR(this, TOK_UNTERMINATED_SUBSHELL, PARAN_ERROR, this->orig_buff + offset_of_open_paran);
break;
}
case mode_array_brackets:
case mode_array_brackets_and_subshell:
{
size_t offset_of_bracket = 0;
TOK_CALL_ERROR(this, TOK_UNTERMINATED_SUBSHELL, SQUARE_BRACKET_ERROR, this->orig_buff + offset_of_bracket); // TOK_UNTERMINATED_SUBSHELL is a lie but nobody actually looks at it
break;
}
default:
assert(0 && "Unexpected mode in read_string");
break;
}
return;
}
len = this->buff - start;
this->last_token.assign(start, len);
this->last_type = TOK_STRING;
}
/**
Read the next token as a comment.
*/
void tokenizer_t::read_comment()
{
const wchar_t *start = this->buff;
while (*(this->buff)!= L'\n' && *(this->buff)!= L'\0')
this->buff++;
size_t len = this->buff - start;
this->last_token.assign(start, len);
this->last_type = TOK_COMMENT;
}
/* Reads a redirection or an "fd pipe" (like 2>|) from a string. Returns how many characters were consumed. If zero, then this string was not a redirection.
Also returns by reference the redirection mode, and the fd to redirection. If there is overflow, *out_fd is set to -1.
*/
static size_t read_redirection_or_fd_pipe(const wchar_t *buff, enum token_type *out_redirection_mode, int *out_fd)
{
bool errored = false;
int fd = 0;
enum token_type redirection_mode = TOK_NONE;
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');
}
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'>':
fd = STDOUT_FILENO;
break;
case L'<':
fd = STDIN_FILENO;
break;
case L'^':
fd = STDERR_FILENO;
break;
default:
errored = true;
break;
}
}
/* Either way we should have ended on the redirection character itself like '>' */
wchar_t redirect_char = buff[idx++]; //note increment of idx
if (redirect_char == L'>' || redirect_char == L'^')
{
redirection_mode = TOK_REDIRECT_OUT;
if (buff[idx] == redirect_char)
{
/* Doubled up like ^^ or >>. That means append */
redirection_mode = TOK_REDIRECT_APPEND;
idx++;
}
}
else if (redirect_char == L'<')
{
redirection_mode = TOK_REDIRECT_IN;
}
else
{
/* Something else */
errored = true;
}
/* Optional characters like & or ?, or the pipe char | */
wchar_t opt_char = buff[idx];
if (opt_char == L'&')
{
redirection_mode = TOK_REDIRECT_FD;
idx++;
}
else if (opt_char == L'?')
{
redirection_mode = TOK_REDIRECT_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. */
redirection_mode = TOK_PIPE;
idx++;
}
/* Don't return valid-looking stuff on error */
if (errored)
{
idx = 0;
redirection_mode = TOK_NONE;
}
/* Return stuff */
if (out_redirection_mode != NULL)
*out_redirection_mode = redirection_mode;
if (out_fd != NULL)
*out_fd = fd;
return idx;
}
enum token_type redirection_type_for_string(const wcstring &str, int *out_fd)
{
enum token_type mode = TOK_NONE;
int fd = 0;
read_redirection_or_fd_pipe(str.c_str(), &mode, &fd);
/* Redirections only, no pipes */
if (mode == TOK_PIPE || fd < 0)
mode = TOK_NONE;
if (out_fd != NULL)
*out_fd = fd;
return mode;
}
int fd_redirected_by_pipe(const wcstring &str)
{
/* Hack for the common case */
if (str == L"|")
{
return STDOUT_FILENO;
}
enum token_type mode = TOK_NONE;
int fd = 0;
read_redirection_or_fd_pipe(str.c_str(), &mode, &fd);
/* Pipes only */
if (mode != TOK_PIPE || fd < 0)
fd = -1;
return fd;
}
int oflags_for_redirection_type(enum token_type type)
{
switch (type)
{
case TOK_REDIRECT_APPEND:
return O_CREAT | O_APPEND | O_WRONLY;
case TOK_REDIRECT_OUT:
return O_CREAT | O_WRONLY | O_TRUNC;
case TOK_REDIRECT_NOCLOB:
return O_CREAT | O_EXCL | O_WRONLY;
case TOK_REDIRECT_IN:
return O_RDONLY;
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 my_iswspace(wchar_t c)
{
return c != L'\n' && iswspace(c);
}
void tokenizer_t::tok_next()
{
if (this->last_type == TOK_ERROR)
{
this->has_next=false;
return;
}
if (!this->has_next)
{
/* wprintf( L"EOL\n" );*/
this->last_type = TOK_END;
return;
}
while (1)
{
if (this->buff[0] == L'\\' && this->buff[1] == L'\n')
{
this->buff += 2;
this->continue_line_after_comment = true;
}
else if (my_iswspace(this->buff[0]))
{
this->buff++;
}
else
{
break;
}
}
while (*this->buff == L'#')
{
if (this->show_comments)
{
this->last_pos = this->buff - this->orig_buff;
this->read_comment();
if (this->buff[0] == L'\n' && this->continue_line_after_comment)
this->buff++;
return;
}
else
{
while (*(this->buff)!= L'\n' && *(this->buff)!= L'\0')
this->buff++;
if (this->buff[0] == L'\n' && this->continue_line_after_comment)
this->buff++;
}
while (my_iswspace(*(this->buff))) {
this->buff++;
}
}
this->continue_line_after_comment = false;
this->last_pos = this->buff - this->orig_buff;
switch (*this->buff)
{
case L'\0':
this->last_type = TOK_END;
/*fwprintf( stderr, L"End of string\n" );*/
this->has_next = false;
break;
case 13: // carriage return
case L'\n':
case L';':
this->last_type = TOK_END;
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++;
}
}
this->last_token.clear();
break;
case L'&':
this->last_type = TOK_BACKGROUND;
this->buff++;
break;
case L'|':
this->last_token = L"1";
this->last_type = TOK_PIPE;
this->buff++;
break;
case L'>':
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! */
enum token_type mode = TOK_NONE;
int fd = -1;
size_t consumed = read_redirection_or_fd_pipe(this->buff, &mode, &fd);
if (consumed == 0 || fd < 0)
{
TOK_CALL_ERROR(this, TOK_OTHER, REDIRECT_ERROR, this->buff);
}
else
{
this->buff += consumed;
this->last_type = mode;
this->last_token = to_string(fd);
}
}
break;
default:
{
/* Maybe a redirection like '2>&1', maybe a pipe like 2>|, maybe just a string */
const wchar_t *error_location = this->buff;
size_t consumed = 0;
enum token_type mode = TOK_NONE;
int fd = -1;
if (iswdigit(*this->buff))
consumed = read_redirection_or_fd_pipe(this->buff, &mode, &fd);
if (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 (mode == TOK_PIPE && fd == 0)
{
TOK_CALL_ERROR(this, TOK_OTHER, PIPE_ERROR, error_location);
}
else
{
this->buff += consumed;
this->last_type = mode;
this->last_token = to_string(fd);
}
}
else
{
/* Not a redirection or pipe, so just a string */
this->read_string();
}
}
break;
}
}
wcstring tok_first(const wcstring &str)
{
wcstring result;
tokenizer_t t(str.c_str(), TOK_SQUASH_ERRORS);
tok_t token;
if (t.next(&token) && token.type == TOK_STRING)
{
result.swap(token.text);
}
return result;
}
bool move_word_state_machine_t::consume_char_punctuation(wchar_t c)
{
enum
{
s_always_one = 0,
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;
state = s_whitespace;
break;
case s_whitespace:
if (iswspace(c))
{
/* Consumed whitespace */
consumed = true;
}
else
{
state = s_alphanumeric;
}
break;
case s_alphanumeric:
if (iswalnum(c))
{
/* Consumed alphanumeric */
consumed = true;
}
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) && ! 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
};
//printf("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 whitespace */
consumed = true;
}
else if (c == L'/' || is_path_component_character(c))
{
/* Path component */
state = s_slash;
}
else
{
/* Path separator */
state = s_separator;
}
break;
case s_separator:
if (! iswspace(c) && ! is_path_component_character(c))
{
/* Consumed separator */
consumed = true;
}
else
{
state = s_end;
}
break;
case s_slash:
if (c == L'/')
{
/* Consumed slash */
consumed = true;
}
else
{
state = s_path_component_characters;
}
break;
case s_path_component_characters:
if (is_path_component_character(c))
{
/* Consumed string character except slash */
consumed = true;
}
else
{
state = s_end;
}
break;
/* We won't get here, but keep the compiler happy */
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:
/* Always consume the first character */
consumed = true;
state = s_blank;
break;
case s_blank:
if (iswblank(c))
{
/* Consumed whitespace */
consumed = true;
}
else
{
state = s_graph;
}
break;
case s_graph:
if (iswgraph(c))
{
/* Consumed printable non-space */
consumed = true;
}
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);
default:
return false;
}
}
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;
}