// Various mostly unrelated utility functions related to parsing, loading and evaluating fish code.
//
// This library can be seen as a 'toolbox' for functions that are used in many places in fish and
// that are somehow related to parsing the code.
#include "config.h" // IWYU pragma: keep
#include "parse_util.h"
#include <stdarg.h>
#include <stdlib.h>
#include <cwchar>
#include <memory>
#include <string>
#include <type_traits>
#include "ast.h"
#include "builtin.h"
#include "common.h"
#include "expand.h"
#include "fallback.h" // IWYU pragma: keep
#include "future_feature_flags.h"
#include "parse_constants.h"
#include "parse_util.h"
#include "parser.h"
#include "tokenizer.h"
#include "wcstringutil.h"
#include "wildcard.h"
#include "wutil.h" // IWYU pragma: keep
/// Error message for use of backgrounded commands before and/or.
#define BOOL_AFTER_BACKGROUND_ERROR_MSG \
_(L"The '%ls' command can not be used immediately after a backgrounded job")
/// Error message for backgrounded commands as conditionals.
#define BACKGROUND_IN_CONDITIONAL_ERROR_MSG \
_(L"Backgrounded commands can not be used as conditionals")
/// Error message for arguments to 'end'
#define END_ARG_ERR_MSG _(L"'end' does not take arguments. Did you forget a ';'?")
/// Maximum length of a variable name to show in error reports before truncation
static constexpr int var_err_len = 16;
int parse_util_lineno(const wchar_t *str, size_t offset) {
if (!str) return 0;
int res = 1;
for (size_t i = 0; i < offset && str[i] != L'\0'; i++) {
if (str[i] == L'\n') {
res++;
}
}
return res;
}
int parse_util_get_line_from_offset(const wcstring &str, size_t pos) {
const wchar_t *buff = str.c_str();
int count = 0;
for (size_t i = 0; i < pos; i++) {
if (!buff[i]) {
return -1;
}
if (buff[i] == L'\n') {
count++;
}
}
return count;
}
size_t parse_util_get_offset_from_line(const wcstring &str, int line) {
const wchar_t *buff = str.c_str();
size_t i;
int count = 0;
if (line < 0) return static_cast<size_t>(-1);
if (line == 0) return 0;
for (i = 0;; i++) {
if (!buff[i]) return static_cast<size_t>(-1);
if (buff[i] == L'\n') {
count++;
if (count == line) {
return i + 1;
}
}
}
}
size_t parse_util_get_offset(const wcstring &str, int line, long line_offset) {
size_t off = parse_util_get_offset_from_line(str, line);
size_t off2 = parse_util_get_offset_from_line(str, line + 1);
if (off == static_cast<size_t>(-1)) return static_cast<size_t>(-1);
if (off2 == static_cast<size_t>(-1)) off2 = str.length() + 1;
if (line_offset < 0) line_offset = 0; //!OCLINT(parameter reassignment)
if (static_cast<size_t>(line_offset) >= off2 - off - 1) {
line_offset = off2 - off - 1; //!OCLINT(parameter reassignment)
}
return off + line_offset;
}
static int parse_util_locate_brackets_of_type(const wchar_t *in, wchar_t **begin, wchar_t **end,
bool allow_incomplete, wchar_t open_type,
wchar_t close_type) {
// open_type is typically ( or [, and close type is the corresponding value.
wchar_t *pos;
bool escaped = false;
bool syntax_error = false;
int paran_count = 0;
wchar_t *paran_begin = nullptr, *paran_end = nullptr;
assert(in && "null parameter");
for (pos = const_cast<wchar_t *>(in); *pos; pos++) {
if (!escaped) {
if (std::wcschr(L"\'\"", *pos)) {
wchar_t *q_end = quote_end(pos);
if (q_end && *q_end) {
pos = q_end;
} else {
break;
}
} else {
if (*pos == open_type) {
if ((paran_count == 0) && (paran_begin == nullptr)) {
paran_begin = pos;
}
paran_count++;
} else if (*pos == close_type) {
paran_count--;
if ((paran_count == 0) && (paran_end == nullptr)) {
paran_end = pos;
break;
}
if (paran_count < 0) {
syntax_error = true;
break;
}
}
}
}
if (*pos == '\\') {
escaped = !escaped;
} else {
escaped = false;
}
}
syntax_error |= (paran_count < 0);
syntax_error |= ((paran_count > 0) && (!allow_incomplete));
if (syntax_error) {
return -1;
}
if (paran_begin == nullptr) {
return 0;
}
if (begin) {
*begin = paran_begin;
}
if (end) {
*end = paran_count ? const_cast<wchar_t *>(in) + std::wcslen(in) : paran_end;
}
return 1;
}
int parse_util_locate_cmdsubst(const wchar_t *in, wchar_t **begin, wchar_t **end,
bool accept_incomplete) {
return parse_util_locate_brackets_of_type(in, begin, end, accept_incomplete, L'(', L')');
}
int parse_util_locate_slice(const wchar_t *in, wchar_t **begin, wchar_t **end,
bool accept_incomplete) {
return parse_util_locate_brackets_of_type(in, begin, end, accept_incomplete, L'[', L']');
}
static int parse_util_locate_brackets_range(const wcstring &str, size_t *inout_cursor_offset,
wcstring *out_contents, size_t *out_start,
size_t *out_end, bool accept_incomplete,
wchar_t open_type, wchar_t close_type) {
// Clear the return values.
if (out_contents != nullptr) out_contents->clear();
*out_start = 0;
*out_end = str.size();
// Nothing to do if the offset is at or past the end of the string.
if (*inout_cursor_offset >= str.size()) return 0;
// Defer to the wonky version.
const wchar_t *const buff = str.c_str();
const wchar_t *const valid_range_start = buff + *inout_cursor_offset,
*valid_range_end = buff + str.size();
wchar_t *bracket_range_begin = nullptr, *bracket_range_end = nullptr;
int ret = parse_util_locate_brackets_of_type(valid_range_start, &bracket_range_begin,
&bracket_range_end, accept_incomplete, open_type,
close_type);
if (ret <= 0) {
return ret;
}
// The command substitutions must not be NULL and must be in the valid pointer range, and
// the end must be bigger than the beginning.
assert(bracket_range_begin != nullptr && bracket_range_begin >= valid_range_start &&
bracket_range_begin <= valid_range_end);
assert(bracket_range_end != nullptr && bracket_range_end > bracket_range_begin &&
bracket_range_end >= valid_range_start && bracket_range_end <= valid_range_end);
// Assign the substring to the out_contents.
const wchar_t *interior_begin = bracket_range_begin + 1;
if (out_contents != nullptr) {
out_contents->assign(interior_begin, bracket_range_end - interior_begin);
}
// Return the start and end.
*out_start = bracket_range_begin - buff;
*out_end = bracket_range_end - buff;
// Update the inout_cursor_offset. Note this may cause it to exceed str.size(), though
// overflow is not likely.
*inout_cursor_offset = 1 + *out_end;
return ret;
}
int parse_util_locate_cmdsubst_range(const wcstring &str, size_t *inout_cursor_offset,
wcstring *out_contents, size_t *out_start, size_t *out_end,
bool accept_incomplete) {
return parse_util_locate_brackets_range(str, inout_cursor_offset, out_contents, out_start,
out_end, accept_incomplete, L'(', L')');
}
void parse_util_cmdsubst_extent(const wchar_t *buff, size_t cursor_pos, const wchar_t **a,
const wchar_t **b) {
assert(buff && "Null buffer");
const wchar_t *const cursor = buff + cursor_pos;
const size_t bufflen = std::wcslen(buff);
assert(cursor_pos <= bufflen);
// ap and bp are the beginning and end of the tightest command substitution found so far.
const wchar_t *ap = buff, *bp = buff + bufflen;
const wchar_t *pos = buff;
for (;;) {
wchar_t *begin = nullptr, *end = nullptr;
if (parse_util_locate_cmdsubst(pos, &begin, &end, true) <= 0) {
// No subshell found, all done.
break;
}
// Interpret NULL to mean the end.
if (end == nullptr) {
end = const_cast<wchar_t *>(buff) + bufflen;
}
if (begin < cursor && end >= cursor) {
// This command substitution surrounds the cursor, so it's a tighter fit.
begin++;
ap = begin;
bp = end;
// pos is where to begin looking for the next one. But if we reached the end there's no
// next one.
if (begin >= end) break;
pos = begin + 1;
} else if (begin >= cursor) {
// This command substitution starts at or after the cursor. Since it was the first
// command substitution in the string, we're done.
break;
} else {
// This command substitution ends before the cursor. Skip it.
assert(end < cursor);
pos = end + 1;
assert(pos <= buff + bufflen);
}
}
if (a != nullptr) *a = ap;
if (b != nullptr) *b = bp;
}
/// Get the beginning and end of the job or process definition under the cursor.
static void job_or_process_extent(bool process, const wchar_t *buff, size_t cursor_pos,
const wchar_t **a, const wchar_t **b,
std::vector<tok_t> *tokens) {
assert(buff && "Null buffer");
const wchar_t *begin = nullptr, *end = nullptr;
int finished = 0;
if (a) *a = nullptr;
if (b) *b = nullptr;
parse_util_cmdsubst_extent(buff, cursor_pos, &begin, &end);
if (!end || !begin) {
return;
}
assert(cursor_pos >= static_cast<size_t>(begin - buff));
const size_t pos = cursor_pos - (begin - buff);
if (a) *a = begin;
if (b) *b = end;
const wcstring buffcpy(begin, end);
tokenizer_t tok(buffcpy.c_str(), TOK_ACCEPT_UNFINISHED);
maybe_t<tok_t> token{};
while ((token = tok.next()) && !finished) {
size_t tok_begin = token->offset;
switch (token->type) {
case token_type_t::pipe: {
if (!process) {
break;
}
}
/* FALLTHROUGH */
case token_type_t::end:
case token_type_t::background:
case token_type_t::andand:
case token_type_t::oror:
case token_type_t::comment: {
if (tok_begin >= pos) {
finished = 1;
if (b) *b = const_cast<wchar_t *>(begin) + tok_begin;
} else {
// Statement at cursor might start after this token.
if (a) *a = const_cast<wchar_t *>(begin) + tok_begin + token->length;
if (tokens) tokens->clear();
}
continue; // Do not add this to tokens
}
default: {
break;
}
}
if (tokens) tokens->push_back(*token);
}
}
void parse_util_process_extent(const wchar_t *buff, size_t pos, const wchar_t **a,
const wchar_t **b, std::vector<tok_t> *tokens) {
job_or_process_extent(true, buff, pos, a, b, tokens);
}
void parse_util_job_extent(const wchar_t *buff, size_t pos, const wchar_t **a, const wchar_t **b) {
job_or_process_extent(false, buff, pos, a, b, nullptr);
}
void parse_util_token_extent(const wchar_t *buff, size_t cursor_pos, const wchar_t **tok_begin,
const wchar_t **tok_end, const wchar_t **prev_begin,
const wchar_t **prev_end) {
assert(buff && "Null buffer");
const wchar_t *a = nullptr, *b = nullptr, *pa = nullptr, *pb = nullptr;
const wchar_t *cmdsubst_begin, *cmdsubst_end;
parse_util_cmdsubst_extent(buff, cursor_pos, &cmdsubst_begin, &cmdsubst_end);
if (!cmdsubst_end || !cmdsubst_begin) {
return;
}
// pos is equivalent to cursor_pos within the range of the command substitution {begin, end}.
size_t offset_within_cmdsubst = cursor_pos - (cmdsubst_begin - buff);
size_t bufflen = std::wcslen(buff);
a = cmdsubst_begin + offset_within_cmdsubst;
b = a;
pa = cmdsubst_begin + offset_within_cmdsubst;
pb = pa;
assert(cmdsubst_begin >= buff);
assert(cmdsubst_begin <= (buff + bufflen));
assert(cmdsubst_end >= cmdsubst_begin);
assert(cmdsubst_end <= (buff + bufflen));
const wcstring buffcpy = wcstring(cmdsubst_begin, cmdsubst_end - cmdsubst_begin);
tokenizer_t tok(buffcpy.c_str(), TOK_ACCEPT_UNFINISHED);
while (maybe_t<tok_t> token = tok.next()) {
size_t tok_begin = token->offset;
size_t tok_end = tok_begin;
// Calculate end of token.
if (token->type == token_type_t::string) {
tok_end += token->length;
}
// Cursor was before beginning of this token, means that the cursor is between two tokens,
// so we set it to a zero element string and break.
if (tok_begin > offset_within_cmdsubst) {
a = b = cmdsubst_begin + offset_within_cmdsubst;
break;
}
// If cursor is inside the token, this is the token we are looking for. If so, set a and b
// and break.
if (token->type == token_type_t::string && tok_end >= offset_within_cmdsubst) {
a = cmdsubst_begin + token->offset;
b = a + token->length;
break;
}
// Remember previous string token.
if (token->type == token_type_t::string) {
pa = cmdsubst_begin + token->offset;
pb = pa + token->length;
}
}
if (tok_begin) *tok_begin = a;
if (tok_end) *tok_end = b;
if (prev_begin) *prev_begin = pa;
if (prev_end) *prev_end = pb;
assert(pa >= buff);
assert(pa <= (buff + bufflen));
assert(pb >= pa);
assert(pb <= (buff + bufflen));
}
wcstring parse_util_unescape_wildcards(const wcstring &str) {
wcstring result;
result.reserve(str.size());
bool unesc_qmark = !feature_test(features_t::qmark_noglob);
const wchar_t *const cs = str.c_str();
for (size_t i = 0; cs[i] != L'\0'; i++) {
if (cs[i] == L'*') {
result.push_back(ANY_STRING);
} else if (cs[i] == L'?' && unesc_qmark) {
result.push_back(ANY_CHAR);
} else if (cs[i] == L'\\' && cs[i + 1] == L'*') {
result.push_back(cs[i + 1]);
i += 1;
} else if (cs[i] == L'\\' && cs[i + 1] == L'?' && unesc_qmark) {
result.push_back(cs[i + 1]);
i += 1;
} else if (cs[i] == L'\\' && cs[i + 1] == L'\\') {
// Not a wildcard, but ensure the next iteration doesn't see this escaped backslash.
result.append(L"\\\\");
i += 1;
} else {
result.push_back(cs[i]);
}
}
return result;
}
/// Find the outermost quoting style of current token. Returns 0 if token is not quoted.
static wchar_t get_quote(const wcstring &cmd_str, size_t len) {
size_t i = 0;
wchar_t res = 0;
const wchar_t *const cmd = cmd_str.c_str();
while (true) {
if (!cmd[i]) break;
if (cmd[i] == L'\\') {
i++;
if (!cmd[i]) break;
i++;
} else {
if (cmd[i] == L'\'' || cmd[i] == L'\"') {
const wchar_t *end = quote_end(&cmd[i]);
// std::fwprintf( stderr, L"Jump %d\n", end-cmd );
if ((end == nullptr) || (!*end) || (end > cmd + len)) {
res = cmd[i];
break;
}
i = end - cmd + 1;
} else
i++;
}
}
return res;
}
void parse_util_get_parameter_info(const wcstring &cmd, const size_t pos, wchar_t *quote,
size_t *offset, token_type_t *out_type) {
size_t prev_pos = 0;
wchar_t last_quote = L'\0';
tokenizer_t tok(cmd.c_str(), TOK_ACCEPT_UNFINISHED);
while (auto token = tok.next()) {
if (token->offset > pos) break;
if (token->type == token_type_t::string)
last_quote = get_quote(tok.text_of(*token), pos - token->offset);
if (out_type != nullptr) *out_type = token->type;
prev_pos = token->offset;
}
wchar_t *cmd_tmp = wcsdup(cmd.c_str());
cmd_tmp[pos] = 0;
size_t cmdlen = pos;
bool finished = cmdlen != 0;
if (finished) {
finished = (quote == nullptr);
if (finished && std::wcschr(L" \t\n\r", cmd_tmp[cmdlen - 1])) {
finished = cmdlen > 1 && cmd_tmp[cmdlen - 2] == L'\\';
}
}
if (quote) *quote = last_quote;
if (offset != nullptr) {
if (finished) {
while ((cmd_tmp[prev_pos] != 0) && (std::wcschr(L";|", cmd_tmp[prev_pos]) != nullptr))
prev_pos++;
*offset = prev_pos;
} else {
*offset = pos;
}
}
free(cmd_tmp);
}
wcstring parse_util_escape_string_with_quote(const wcstring &cmd, wchar_t quote, bool no_tilde) {
wcstring result;
if (quote == L'\0') {
escape_flags_t flags = ESCAPE_ALL | ESCAPE_NO_QUOTED | (no_tilde ? ESCAPE_NO_TILDE : 0);
result = escape_string(cmd, flags);
} else {
// Here we are going to escape a string with quotes.
// A few characters cannot be represented inside quotes, e.g. newlines. In that case,
// terminate the quote and then re-enter it.
result.reserve(cmd.size());
for (wchar_t c : cmd) {
switch (c) {
case L'\n':
result.append({quote, L'\\', L'n', quote});
break;
case L'\t':
result.append({quote, L'\\', L't', quote});
break;
case L'\b':
result.append({quote, L'\\', L'b', quote});
break;
case L'\r':
result.append({quote, L'\\', L'r', quote});
break;
case L'\\':
result.append({L'\\', L'\\'});
break;
case L'$':
if (quote == L'"') result.push_back(L'\\');
result.push_back(L'$');
break;
default:
if (c == quote) result.push_back(L'\\');
result.push_back(c);
break;
}
}
}
return result;
}
std::vector<int> parse_util_compute_indents(const wcstring &src) {
// Make a vector the same size as the input string, which contains the indents. Initialize them
// to 0.
const size_t src_size = src.size();
std::vector<int> indents(src_size, 0);
// Simple trick: if our source does not contain a newline, then all indents are 0.
if (src.find('\n') == wcstring::npos) {
return indents;
}
// Parse the string. We pass continue_after_error to produce a forest; the trailing indent of
// the last node we visited becomes the input indent of the next. I.e. in the case of 'switch
// foo ; cas', we get an invalid parse tree (since 'cas' is not valid) but we indent it as if it
// were a case item list.
using namespace ast;
auto ast =
ast_t::parse(src, parse_flag_continue_after_error | parse_flag_include_comments |
parse_flag_accept_incomplete_tokens | parse_flag_leave_unterminated);
// Visit all of our nodes. When we get a job_list or case_item_list, increment indent while
// visiting its children.
struct indent_visitor_t {
indent_visitor_t(const wcstring &src, std::vector<int> &indents)
: src(src), indents(indents) {}
void visit(const node_t &node) {
int inc = 0;
int dec = 0;
switch (node.type) {
case type_t::job_list:
case type_t::andor_job_list:
// Job lists are never unwound.
inc = 1;
dec = 1;
break;
// Increment indents for conditions in headers (#1665).
case type_t::job_conjunction:
if (node.parent->type == type_t::while_header ||
node.parent->type == type_t::if_clause) {
inc = 1;
dec = 1;
}
break;
// Increment indents for job_continuation_t if it contains a newline.
// This is a bit of a hack - it indents cases like:
// cmd1 |
// ....cmd2
// but avoids "double indenting" if there's no newline:
// cmd1 | while cmd2
// ....cmd3
// end
// See #7252.
case type_t::job_continuation:
if (has_newline(node.as<job_continuation_t>()->newlines)) {
inc = 1;
dec = 1;
}
break;
// Likewise for && and ||.
case type_t::job_conjunction_continuation:
if (has_newline(node.as<job_conjunction_continuation_t>()->newlines)) {
inc = 1;
dec = 1;
}
break;
case type_t::case_item_list:
// Here's a hack. Consider:
// switch abc
// cas
//
// fish will see that 'cas' is not valid inside a switch statement because it is
// not "case". It will then unwind back to the top level job list, producing a
// parse tree like:
//
// job_list
// switch_job
// <err>
// normal_job
// cas
//
// And so we will think that the 'cas' job is at the same level as the switch.
// To address this, if we see that the switch statement was not closed, do not
// decrement the indent afterwards.
inc = 1;
dec = node.parent->as<switch_statement_t>()->end.unsourced ? 0 : 1;
break;
case type_t::token_base: {
auto tok = node.as<token_base_t>();
if (node.parent->type == type_t::begin_header &&
tok->type == parse_token_type_t::end) {
// The newline after "begin" is optional, so it is part of the header.
// The header is not in the indented block, so indent the newline here.
if (node.source(src) == L"\n") {
inc = 1;
dec = 1;
}
}
break;
}
default:
break;
}
auto range = node.source_range();
if (range.length > 0 && node.category == category_t::leaf) {
record_line_continuations_until(range.start);
std::fill(indents.begin() + last_leaf_end, indents.begin() + range.start,
last_indent);
}
indent += inc;
// If we increased the indentation, apply it to the remainder of the string, even if the
// list is empty. For example (where _ represents the cursor):
//
// if foo
// _
//
// we want to indent the newline.
if (inc) {
last_indent = indent;
}
// If this is a leaf node, apply the current indentation.
if (node.category == category_t::leaf && range.length > 0) {
std::fill(indents.begin() + range.start, indents.begin() + range.end(), indent);
last_leaf_end = range.start + range.length;
last_indent = indent;
}
node_visitor(*this).accept_children_of(&node);
indent -= dec;
}
/// \return whether a maybe_newlines node contains at least one newline.
bool has_newline(const maybe_newlines_t &nls) const {
return nls.source(src).find(L'\n') != wcstring::npos;
}
void record_line_continuations_until(size_t offset) {
wcstring gap_text = src.substr(last_leaf_end, offset - last_leaf_end);
size_t escaped_nl = gap_text.find(L"\\\n");
if (escaped_nl == wcstring::npos) return;
auto line_end = gap_text.begin() + escaped_nl;
if (std::find(gap_text.begin(), line_end, L'#') != line_end) return;
auto end = src.begin() + offset;
auto newline = src.begin() + last_leaf_end + escaped_nl + 1;
// The gap text might contain multiple newlines if there are multiple lines that
// don't contain an AST node, for example, comment lines, or lines containing only
// the escaped newline.
do {
line_continuations.push_back(newline - src.begin());
newline = std::find(newline + 1, end, L'\n');
} while (newline != end);
}
// The one-past-the-last index of the most recently encountered leaf node.
// We use this to populate the indents even if there's no tokens in the range.
size_t last_leaf_end{0};
// The last indent which we assigned.
int last_indent{-1};
// The source we are indenting.
const wcstring &src;
// List of indents, which we populate.
std::vector<int> &indents;
// Initialize our starting indent to -1, as our top-level node is a job list which
// will immediately increment it.
int indent{-1};
// List of locations of escaped newline characters.
std::vector<size_t> line_continuations;
};
indent_visitor_t iv(src, indents);
node_visitor(iv).accept(ast.top());
iv.record_line_continuations_until(indents.size());
std::fill(indents.begin() + iv.last_leaf_end, indents.end(), iv.last_indent);
// All newlines now get the *next* indent.
// For example, in this code:
// if true
// stuff
// the newline "belongs" to the if statement as it ends its job.
// But when rendered, it visually belongs to the job list.
size_t idx = src_size;
int next_indent = iv.last_indent;
while (idx--) {
if (src.at(idx) == L'\n') {
bool empty_middle_line = idx + 1 < src_size && src.at(idx + 1) == L'\n';
if (!empty_middle_line) {
indents.at(idx) = next_indent;
}
} else {
next_indent = indents.at(idx);
}
}
// Add an extra level of indentation to continuation lines.
for (size_t idx : iv.line_continuations) {
do {
indents.at(idx)++;
} while (++idx < src_size && src.at(idx) != L'\n');
}
return indents;
}
/// Append a syntax error to the given error list.
static bool append_syntax_error(parse_error_list_t *errors, size_t source_location,
const wchar_t *fmt, ...) {
if (!errors) return true;
parse_error_t error;
error.source_start = source_location;
error.source_length = 0;
error.code = parse_error_syntax;
va_list va;
va_start(va, fmt);
error.text = vformat_string(fmt, va);
va_end(va);
errors->push_back(std::move(error));
return true;
}
/// Returns 1 if the specified command is a builtin that may not be used in a pipeline.
static const wchar_t *const forbidden_pipe_commands[] = {L"exec", L"case", L"break", L"return",
L"continue"};
static int parser_is_pipe_forbidden(const wcstring &word) {
return contains(forbidden_pipe_commands, word);
}
bool parse_util_argument_is_help(const wchar_t *s) {
return std::wcscmp(L"-h", s) == 0 || std::wcscmp(L"--help", s) == 0;
}
// \return a pointer to the first argument node of an argument_or_redirection_list_t, or nullptr if
// there are no arguments.
static const ast::argument_t *get_first_arg(const ast::argument_or_redirection_list_t &list) {
for (const ast::argument_or_redirection_t &v : list) {
if (v.is_argument()) return &v.argument();
}
return nullptr;
}
/// Given a wide character immediately after a dollar sign, return the appropriate error message.
/// For example, if wc is @, then the variable name was $@ and we suggest $argv.
static const wchar_t *error_format_for_character(wchar_t wc) {
switch (wc) {
case L'?': {
return ERROR_NOT_STATUS;
}
case L'#': {
return ERROR_NOT_ARGV_COUNT;
}
case L'@': {
return ERROR_NOT_ARGV_AT;
}
case L'*': {
return ERROR_NOT_ARGV_STAR;
}
case L'$':
case VARIABLE_EXPAND:
case VARIABLE_EXPAND_SINGLE:
case VARIABLE_EXPAND_EMPTY: {
return ERROR_NOT_PID;
}
default: {
return ERROR_BAD_VAR_CHAR1;
}
}
}
void parse_util_expand_variable_error(const wcstring &token, size_t global_token_pos,
size_t dollar_pos, parse_error_list_t *errors) {
// Note that dollar_pos is probably VARIABLE_EXPAND or VARIABLE_EXPAND_SINGLE, not a literal
// dollar sign.
assert(errors != nullptr);
assert(dollar_pos < token.size());
const bool double_quotes = token.at(dollar_pos) == VARIABLE_EXPAND_SINGLE;
const size_t start_error_count = errors->size();
const size_t global_dollar_pos = global_token_pos + dollar_pos;
const size_t global_after_dollar_pos = global_dollar_pos + 1;
wchar_t char_after_dollar = dollar_pos + 1 >= token.size() ? 0 : token.at(dollar_pos + 1);
switch (char_after_dollar) {
case BRACE_BEGIN:
case L'{': {
// The BRACE_BEGIN is for unquoted, the { is for quoted. Anyways we have (possible
// quoted) ${. See if we have a }, and the stuff in between is variable material. If so,
// report a bracket error. Otherwise just complain about the ${.
bool looks_like_variable = false;
size_t closing_bracket =
token.find(char_after_dollar == L'{' ? L'}' : wchar_t(BRACE_END), dollar_pos + 2);
wcstring var_name;
if (closing_bracket != wcstring::npos) {
size_t var_start = dollar_pos + 2, var_end = closing_bracket;
var_name = wcstring(token, var_start, var_end - var_start);
looks_like_variable = valid_var_name(var_name);
}
if (looks_like_variable) {
append_syntax_error(
errors, global_after_dollar_pos,
double_quotes ? ERROR_BRACKETED_VARIABLE_QUOTED1 : ERROR_BRACKETED_VARIABLE1,
truncate(var_name, var_err_len).c_str());
} else {
append_syntax_error(errors, global_after_dollar_pos, ERROR_BAD_VAR_CHAR1, L'{');
}
break;
}
case INTERNAL_SEPARATOR: {
// e.g.: echo foo"$"baz
// These are only ever quotes, not command substitutions. Command substitutions are
// handled earlier.
append_syntax_error(errors, global_dollar_pos, ERROR_NO_VAR_NAME);
break;
}
case '(': {
// e.g.: 'echo "foo$(bar)baz"
// Try to determine what's in the parens.
wcstring token_after_parens;
wcstring paren_text;
size_t open_parens = dollar_pos + 1, cmdsub_start = 0, cmdsub_end = 0;
if (parse_util_locate_cmdsubst_range(token, &open_parens, &paren_text, &cmdsub_start,
&cmdsub_end, true) > 0) {
token_after_parens = tok_first(paren_text);
}
// Make sure we always show something.
if (token_after_parens.empty()) {
token_after_parens = get_ellipsis_str();
}
append_syntax_error(errors, global_dollar_pos, ERROR_BAD_VAR_SUBCOMMAND1,
truncate(token_after_parens, var_err_len).c_str());
break;
}
case L'\0': {
append_syntax_error(errors, global_dollar_pos, ERROR_NO_VAR_NAME);
break;
}
default: {
wchar_t token_stop_char = char_after_dollar;
// Unescape (see issue #50).
if (token_stop_char == ANY_CHAR)
token_stop_char = L'?';
else if (token_stop_char == ANY_STRING || token_stop_char == ANY_STRING_RECURSIVE)
token_stop_char = L'*';
// Determine which error message to use. The format string may not consume all the
// arguments we pass but that's harmless.
const wchar_t *error_fmt = error_format_for_character(token_stop_char);
append_syntax_error(errors, global_after_dollar_pos, error_fmt, token_stop_char);
break;
}
}
// We should have appended exactly one error.
assert(errors->size() == start_error_count + 1);
}
/// Detect cases like $(abc). Given an arg like foo(bar), let arg_src be foo and cmdsubst_src be
/// bar. If arg ends with VARIABLE_EXPAND, then report an error.
static parser_test_error_bits_t detect_dollar_cmdsub_errors(size_t arg_src_offset,
const wcstring &arg_src,
const wcstring &cmdsubst_src,
parse_error_list_t *out_errors) {
parser_test_error_bits_t result_bits = 0;
wcstring unescaped_arg_src;
if (!unescape_string(arg_src, &unescaped_arg_src, UNESCAPE_SPECIAL) ||
unescaped_arg_src.empty()) {
return result_bits;
}
wchar_t last = unescaped_arg_src.at(unescaped_arg_src.size() - 1);
if (last == VARIABLE_EXPAND) {
result_bits |= PARSER_TEST_ERROR;
if (out_errors != nullptr) {
wcstring subcommand_first_token = tok_first(cmdsubst_src);
if (subcommand_first_token.empty()) {
// e.g. $(). Report somthing.
subcommand_first_token = get_ellipsis_str();
}
append_syntax_error(
out_errors,
arg_src_offset + arg_src.size() - 1, // global position of the dollar
ERROR_BAD_VAR_SUBCOMMAND1, truncate(subcommand_first_token, var_err_len).c_str());
}
}
return result_bits;
}
/// Test if this argument contains any errors. Detected errors include syntax errors in command
/// substitutions, improperly escaped characters and improper use of the variable expansion
/// operator.
parser_test_error_bits_t parse_util_detect_errors_in_argument(const ast::argument_t &arg,
const wcstring &arg_src,
parse_error_list_t *out_errors) {
maybe_t<source_range_t> source_range = arg.try_source_range();
if (!source_range.has_value()) return 0;
size_t source_start = source_range->start;
parser_test_error_bits_t err = 0;
size_t cursor = 0;
wcstring subst;
bool do_loop = true;
while (do_loop) {
size_t paren_begin = 0;
size_t paren_end = 0;
switch (parse_util_locate_cmdsubst_range(arg_src, &cursor, &subst, &paren_begin, &paren_end,
false)) {
case -1: {
err |= PARSER_TEST_ERROR;
if (out_errors) {
append_syntax_error(out_errors, source_start, L"Mismatched parenthesis");
}
return err;
}
case 0: {
do_loop = false;
break;
}
case 1: {
assert(paren_begin < paren_end && "Parens out of order?");
parse_error_list_t subst_errors;
err |= parse_util_detect_errors(subst, &subst_errors);
// Our command substitution produced error offsets relative to its source. Tweak the
// offsets of the errors in the command substitution to account for both its offset
// within the string, and the offset of the node.
size_t error_offset = paren_begin + 1 + source_start;
parse_error_offset_source_start(&subst_errors, error_offset);
if (out_errors != nullptr) {
out_errors->insert(out_errors->end(), subst_errors.begin(), subst_errors.end());
// Hackish. Take this opportunity to report $(...) errors. We do this because
// after we've replaced with internal separators, we can't distinguish between
// "" and (), and also we no longer have the source of the command substitution.
// As an optimization, this is only necessary if the last character is a $.
if (paren_begin > 0 && arg_src.at(paren_begin - 1) == L'$') {
err |= detect_dollar_cmdsub_errors(
source_start, arg_src.substr(0, paren_begin), subst, out_errors);
}
}
break;
}
default: {
DIE("unexpected parse_util_locate_cmdsubst() return value");
}
}
}
wcstring unesc;
if (!unescape_string(arg_src, &unesc, UNESCAPE_SPECIAL)) {
if (out_errors) {
append_syntax_error(out_errors, source_start, L"Invalid token '%ls'", arg_src.c_str());
}
return 1;
}
// Check for invalid variable expansions.
const size_t unesc_size = unesc.size();
for (size_t idx = 0; idx < unesc_size; idx++) {
if (unesc.at(idx) != VARIABLE_EXPAND && unesc.at(idx) != VARIABLE_EXPAND_SINGLE) {
continue;
}
wchar_t next_char = idx + 1 < unesc_size ? unesc.at(idx + 1) : L'\0';
if (next_char != VARIABLE_EXPAND && next_char != VARIABLE_EXPAND_SINGLE &&
!valid_var_name_char(next_char)) {
err = 1;
if (out_errors) {
// We have something like $$$^.... Back up until we reach the first $.
size_t first_dollar = idx;
while (first_dollar > 0 && (unesc.at(first_dollar - 1) == VARIABLE_EXPAND ||
unesc.at(first_dollar - 1) == VARIABLE_EXPAND_SINGLE)) {
first_dollar--;
}
parse_util_expand_variable_error(unesc, source_start, first_dollar, out_errors);
}
}
}
return err;
}
/// Given that the job given by node should be backgrounded, return true if we detect any errors.
static bool detect_errors_in_backgrounded_job(const ast::job_t &job,
parse_error_list_t *parse_errors) {
using namespace ast;
auto source_range = job.try_source_range();
if (!source_range) return false;
bool errored = false;
// Disallow background in the following cases:
// foo & ; and bar
// foo & ; or bar
// if foo & ; end
// while foo & ; end
const job_conjunction_t *job_conj = job.parent->try_as<job_conjunction_t>();
if (!job_conj) return false;
if (job_conj->parent->try_as<if_clause_t>()) {
errored = append_syntax_error(parse_errors, source_range->start,
BACKGROUND_IN_CONDITIONAL_ERROR_MSG);
} else if (job_conj->parent->try_as<while_header_t>()) {
errored = append_syntax_error(parse_errors, source_range->start,
BACKGROUND_IN_CONDITIONAL_ERROR_MSG);
} else if (const ast::job_list_t *jlist = job_conj->parent->try_as<ast::job_list_t>()) {
// This isn't very complete, e.g. we don't catch 'foo & ; not and bar'.
// Find the index of ourselves in the job list.
size_t index;
for (index = 0; index < jlist->count(); index++) {
if (jlist->at(index) == job_conj) break;
}
assert(index < jlist->count() && "Should have found the job in the list");
// Try getting the next job and check its decorator.
if (const job_conjunction_t *next = jlist->at(index + 1)) {
if (const keyword_base_t *deco = next->decorator.contents.get()) {
assert(
(deco->kw == parse_keyword_t::kw_and || deco->kw == parse_keyword_t::kw_or) &&
"Unexpected decorator keyword");
const wchar_t *deco_name = (deco->kw == parse_keyword_t::kw_and ? L"and" : L"or");
errored = append_syntax_error(parse_errors, deco->source_range().start,
BOOL_AFTER_BACKGROUND_ERROR_MSG, deco_name);
}
}
}
return errored;
}
/// Given a source buffer \p buff_src and decorated statement \p dst within it, return true if there
/// is an error and false if not. \p storage may be used to reduce allocations.
static bool detect_errors_in_decorated_statement(const wcstring &buff_src,
const ast::decorated_statement_t &dst,
wcstring *storage,
parse_error_list_t *parse_errors) {
using namespace ast;
bool errored = false;
auto source_start = dst.source_range().start;
const statement_decoration_t decoration = dst.decoration();
// Determine if the first argument is help.
bool first_arg_is_help = false;
if (const auto *arg = get_first_arg(dst.args_or_redirs)) {
const wcstring &arg_src = arg->source(buff_src, storage);
first_arg_is_help = parse_util_argument_is_help(arg_src.c_str());
}
// Get the statement we are part of.
const statement_t *st = dst.parent->as<statement_t>();
// Walk up to the job.
const ast::job_t *job = nullptr;
for (const node_t *cursor = st; job == nullptr; cursor = cursor->parent) {
assert(cursor && "Reached root without finding a job");
job = cursor->try_as<ast::job_t>();
}
assert(job && "Should have found the job");
// Check our pipeline position.
pipeline_position_t pipe_pos;
if (job->continuation.empty()) {
pipe_pos = pipeline_position_t::none;
} else if (&job->statement == st) {
pipe_pos = pipeline_position_t::first;
} else {
pipe_pos = pipeline_position_t::subsequent;
}
// Check that we don't try to pipe through exec.
bool is_in_pipeline = (pipe_pos != pipeline_position_t::none);
if (is_in_pipeline && decoration == statement_decoration_t::exec) {
errored = append_syntax_error(parse_errors, source_start, EXEC_ERR_MSG, L"exec");
}
// This is a somewhat stale check that 'and' and 'or' are not in pipelines, except at the
// beginning. We can't disallow them as commands entirely because we need to support 'and
// --help', etc.
if (pipe_pos == pipeline_position_t::subsequent) {
// check if our command is 'and' or 'or'. This is very clumsy; we don't catch e.g. quoted
// commands.
const wcstring &command = dst.command.source(buff_src, storage);
if (command == L"and" || command == L"or") {
errored =
append_syntax_error(parse_errors, source_start, EXEC_ERR_MSG, command.c_str());
}
}
const wcstring &unexp_command = dst.command.source(buff_src, storage);
if (!unexp_command.empty()) {
wcstring command;
// Check that we can expand the command.
if (expand_to_command_and_args(unexp_command, operation_context_t::empty(), &command,
nullptr, parse_errors,
true /* skip wildcards */) == expand_result_t::error) {
errored = true;
parse_error_offset_source_start(parse_errors, source_start);
}
// Check that pipes are sound.
if (!errored && parser_is_pipe_forbidden(command) && is_in_pipeline) {
errored =
append_syntax_error(parse_errors, source_start, EXEC_ERR_MSG, command.c_str());
}
// Check that we don't return from outside a function. But we allow it if it's
// 'return --help'.
if (!errored && command == L"return" && !first_arg_is_help) {
// See if we are in a function.
bool found_function = false;
for (const node_t *cursor = &dst; cursor != nullptr; cursor = cursor->parent) {
if (const auto *bs = cursor->try_as<block_statement_t>()) {
if (bs->header->type == type_t::function_header) {
found_function = true;
break;
}
}
}
if (!found_function) {
errored = append_syntax_error(parse_errors, source_start, INVALID_RETURN_ERR_MSG);
}
}
// Check that we don't break or continue from outside a loop.
if (!errored && (command == L"break" || command == L"continue") && !first_arg_is_help) {
// Walk up until we hit a 'for' or 'while' loop. If we hit a function first,
// stop the search; we can't break an outer loop from inside a function.
// This is a little funny because we can't tell if it's a 'for' or 'while'
// loop from the ancestor alone; we need the header. That is, we hit a
// block_statement, and have to check its header.
bool found_loop = false;
for (const node_t *ancestor = &dst; ancestor != nullptr; ancestor = ancestor->parent) {
const auto *block = ancestor->try_as<block_statement_t>();
if (!block) continue;
if (block->header->type == type_t::for_header ||
block->header->type == type_t::while_header) {
// This is a loop header, so we can break or continue.
found_loop = true;
break;
} else if (block->header->type == type_t::function_header) {
// This is a function header, so we cannot break or
// continue. We stop our search here.
found_loop = false;
break;
}
}
if (!found_loop) {
errored = append_syntax_error(
parse_errors, source_start,
(command == L"break" ? INVALID_BREAK_ERR_MSG : INVALID_CONTINUE_ERR_MSG));
}
}
// Check that we don't do an invalid builtin (issue #1252).
if (!errored && decoration == statement_decoration_t::builtin) {
wcstring command = unexp_command;
if (expand_one(command, expand_flag::skip_cmdsubst, operation_context_t::empty(),
parse_errors) &&
!builtin_exists(unexp_command)) {
errored = append_syntax_error(parse_errors, source_start, UNKNOWN_BUILTIN_ERR_MSG,
unexp_command.c_str());
}
}
}
return errored;
}
// Given we have a trailing argument_or_redirection_list, like `begin; end > /dev/null`, verify that
// there are no arguments in the list.
static bool detect_errors_in_block_redirection_list(
const ast::argument_or_redirection_list_t &args_or_redirs, parse_error_list_t *out_errors) {
if (const auto *first_arg = get_first_arg(args_or_redirs)) {
return append_syntax_error(out_errors, first_arg->source_range().start,
BACKGROUND_IN_CONDITIONAL_ERROR_MSG);
}
return false;
}
parser_test_error_bits_t parse_util_detect_errors(const ast::ast_t &ast, const wcstring &buff_src,
parse_error_list_t *out_errors) {
using namespace ast;
parser_test_error_bits_t res = 0;
// Whether we encountered a parse error.
bool errored = false;
// Whether we encountered an unclosed block. We detect this via an 'end_command' block without
// source.
bool has_unclosed_block = false;
// Whether we encounter a missing statement, i.e. a newline after a pipe. This is found by
// detecting job_continuations that have source for pipes but not the statement.
bool has_unclosed_pipe = false;
// Whether we encounter a missing job, i.e. a newline after && or ||. This is found by
// detecting job_conjunction_continuations that have source for && or || but not the job.
bool has_unclosed_conjunction = false;
// Expand all commands.
// Verify 'or' and 'and' not used inside pipelines.
// Verify pipes via parser_is_pipe_forbidden.
// Verify return only within a function.
// Verify no variable expansions.
wcstring storage;
for (const node_t &node : ast) {
if (const job_continuation_t *jc = node.try_as<job_continuation_t>()) {
// Somewhat clumsy way of checking for a statement without source in a pipeline.
// See if our pipe has source but our statement does not.
if (!jc->pipe.unsourced && !jc->statement.try_source_range().has_value()) {
has_unclosed_pipe = true;
}
} else if (const auto *jcc = node.try_as<job_conjunction_continuation_t>()) {
// Somewhat clumsy way of checking for a job without source in a conjunction.
// See if our conjunction operator (&& or ||) has source but our job does not.
if (!jcc->conjunction.unsourced && !jcc->job.try_source_range().has_value()) {
has_unclosed_conjunction = true;
}
} else if (const argument_t *arg = node.try_as<argument_t>()) {
const wcstring &arg_src = arg->source(buff_src, &storage);
res |= parse_util_detect_errors_in_argument(*arg, arg_src, out_errors);
} else if (const ast::job_t *job = node.try_as<ast::job_t>()) {
// Disallow background in the following cases:
//
// foo & ; and bar
// foo & ; or bar
// if foo & ; end
// while foo & ; end
// If it's not a background job, nothing to do.
if (job->bg) {
errored |= detect_errors_in_backgrounded_job(*job, out_errors);
}
} else if (const ast::decorated_statement_t *stmt = node.try_as<decorated_statement_t>()) {
errored |= detect_errors_in_decorated_statement(buff_src, *stmt, &storage, out_errors);
} else if (const auto *block = node.try_as<block_statement_t>()) {
// If our 'end' had no source, we are unsourced.
if (block->end.unsourced) has_unclosed_block = true;
errored |= detect_errors_in_block_redirection_list(block->args_or_redirs, out_errors);
} else if (const auto *ifs = node.try_as<if_statement_t>()) {
// If our 'end' had no source, we are unsourced.
if (ifs->end.unsourced) has_unclosed_block = true;
errored |= detect_errors_in_block_redirection_list(ifs->args_or_redirs, out_errors);
} else if (const auto *switchs = node.try_as<switch_statement_t>()) {
// If our 'end' had no source, we are unsourced.
if (switchs->end.unsourced) has_unclosed_block = true;
errored |= detect_errors_in_block_redirection_list(switchs->args_or_redirs, out_errors);
}
}
if (errored) res |= PARSER_TEST_ERROR;
if (has_unclosed_block || has_unclosed_pipe || has_unclosed_conjunction)
res |= PARSER_TEST_INCOMPLETE;
return res;
}
parser_test_error_bits_t parse_util_detect_errors(const wcstring &buff_src,
parse_error_list_t *out_errors,
bool allow_incomplete) {
// Whether there's an unclosed quote or subshell, and therefore unfinished. This is only set if
// allow_incomplete is set.
bool has_unclosed_quote_or_subshell = false;
const parse_tree_flags_t parse_flags =
allow_incomplete ? parse_flag_leave_unterminated : parse_flag_none;
// Parse the input string into an ast. Some errors are detected here.
using namespace ast;
parse_error_list_t parse_errors;
auto ast = ast_t::parse(buff_src, parse_flags, &parse_errors);
if (allow_incomplete) {
// Issue #1238: If the only error was unterminated quote, then consider this to have parsed
// successfully.
size_t idx = parse_errors.size();
while (idx--) {
if (parse_errors.at(idx).code == parse_error_tokenizer_unterminated_quote ||
parse_errors.at(idx).code == parse_error_tokenizer_unterminated_subshell) {
// Remove this error, since we don't consider it a real error.
has_unclosed_quote_or_subshell = true;
parse_errors.erase(parse_errors.begin() + idx);
}
}
}
// has_unclosed_quote_or_subshell may only be set if allow_incomplete is true.
assert(!has_unclosed_quote_or_subshell || allow_incomplete);
if (has_unclosed_quote_or_subshell) {
// We do not bother to validate the rest of the tree in this case.
return PARSER_TEST_INCOMPLETE;
}
// Early parse error, stop here.
if (!parse_errors.empty()) {
if (out_errors) vec_append(*out_errors, std::move(parse_errors));
return PARSER_TEST_ERROR;
}
// Defer to the tree-walking version.
return parse_util_detect_errors(ast, buff_src, out_errors);
}
maybe_t<wcstring> parse_util_detect_errors_in_argument_list(const wcstring &arg_list_src,
const wcstring &prefix) {
// Helper to return a description of the first error.
auto get_error_text = [&](const parse_error_list_t &errors) {
assert(!errors.empty() && "Expected an error");
return errors.at(0).describe_with_prefix(arg_list_src, prefix, false /* not interactive */,
false /* don't skip caret */);
};
// Parse the string as a freestanding argument list.
using namespace ast;
parse_error_list_t errors;
auto ast = ast_t::parse_argument_list(arg_list_src, parse_flag_none, &errors);
if (!errors.empty()) {
return get_error_text(errors);
}
// Get the root argument list and extract arguments from it.
// Test each of these.
for (const argument_t &arg : ast.top()->as<freestanding_argument_list_t>()->arguments) {
const wcstring arg_src = arg.source(arg_list_src);
if (parse_util_detect_errors_in_argument(arg, arg_src, &errors)) {
return get_error_text(errors);
}
}
return none();
}