fish-shell/src/parser.h

342 lines
12 KiB
C++

// The fish parser.
#ifndef FISH_PARSER_H
#define FISH_PARSER_H
#include <stddef.h>
#include <unistd.h>
#include <csignal>
#include <list>
#include <memory>
#include <type_traits>
#include <vector>
#include "common.h"
#include "event.h"
#include "expand.h"
#include "parse_constants.h"
#include "parse_tree.h"
#include "proc.h"
class io_chain_t;
/// event_blockage_t represents a block on events of the specified type.
struct event_blockage_t {
/// The types of events to block. This is interpreted as a bitset whete the value is 1 for every
/// bit corresponding to a blocked event type. For example, if EVENT_VARIABLE type events should
/// be blocked, (type & 1<<EVENT_BLOCKED) should be set.
///
/// Note that EVENT_ANY can be used to specify any event.
unsigned int typemask;
};
typedef std::list<event_blockage_t> event_blockage_list_t;
inline bool event_block_list_blocks_type(const event_blockage_list_t &ebls, int type) {
for (event_blockage_list_t::const_iterator iter = ebls.begin(); iter != ebls.end(); ++iter) {
if (iter->typemask & (1 << EVENT_ANY)) return true;
if (iter->typemask & (1 << type)) return true;
}
return false;
}
/// Types of blocks.
enum block_type_t {
WHILE, /// While loop block
FOR, /// For loop block
IF, /// If block
FUNCTION_CALL, /// Function invocation block
FUNCTION_CALL_NO_SHADOW, /// Function invocation block with no variable shadowing
SWITCH, /// Switch block
SUBST, /// Command substitution scope
TOP, /// Outermost block
BEGIN, /// Unconditional block
SOURCE, /// Block created by the . (source) builtin
EVENT, /// Block created on event notifier invocation
BREAKPOINT, /// Breakpoint block
};
/// Possible states for a loop.
enum loop_status_t {
LOOP_NORMAL, /// current loop block executed as normal
LOOP_BREAK, /// current loop block should be removed
LOOP_CONTINUE, /// current loop block should be skipped
};
/// block_t represents a block of commands.
struct block_t {
protected:
/// Protected constructor. Use one of the subclasses below.
explicit block_t(block_type_t t);
private:
/// Type of block.
const block_type_t block_type;
public:
/// Whether execution of the commands in this block should be skipped.
bool skip{false};
/// Status for the current loop block. Can be any of the values from the loop_status enum.
enum loop_status_t loop_status { LOOP_NORMAL };
/// The job that is currently evaluated in the specified block.
shared_ptr<job_t> job{};
/// Name of file that created this block. This string is intern'd.
const wchar_t *src_filename{nullptr};
/// Line number where this block was created.
int src_lineno{0};
/// Whether we should pop the environment variable stack when we're popped off of the block
/// stack.
bool wants_pop_env{false};
/// List of event blocks.
event_blockage_list_t event_blocks{};
block_type_t type() const { return this->block_type; }
/// Description of the block, for debugging.
wcstring description() const;
/// Destructor
virtual ~block_t();
};
struct if_block_t : public block_t {
if_block_t();
};
struct event_block_t : public block_t {
event_t const event;
explicit event_block_t(const event_t &evt);
};
struct function_block_t : public block_t {
const process_t *process;
wcstring name;
function_block_t(const process_t *p, wcstring n, bool shadows);
};
struct source_block_t : public block_t {
const wchar_t *const source_file;
explicit source_block_t(const wchar_t *src);
};
struct for_block_t : public block_t {
for_block_t();
};
struct while_block_t : public block_t {
while_block_t();
};
struct switch_block_t : public block_t {
switch_block_t();
};
struct scope_block_t : public block_t {
explicit scope_block_t(block_type_t type); // must be BEGIN, TOP or SUBST
};
struct breakpoint_block_t : public block_t {
breakpoint_block_t();
};
struct profile_item_t {
/// Time spent executing the specified command, including parse time for nested blocks.
int exec;
/// Time spent parsing the specified command, including execution time for command
/// substitutions.
int parse;
/// The block level of the specified command. nested blocks and command substitutions both
/// increase the block level.
size_t level;
/// If the execution of this command was skipped.
bool skipped;
/// The command string.
wcstring cmd;
};
class parse_execution_context_t;
class completion_t;
class parser_t {
friend class parse_execution_context_t;
private:
/// Indication that we should skip all blocks.
volatile sig_atomic_t cancellation_requested;
/// Indicates that we are within the process of initializing fish.
bool is_within_fish_initialization;
/// The current execution context.
std::unique_ptr<parse_execution_context_t> execution_context;
/// List of called functions, used to help prevent infinite recursion.
wcstring_list_t forbidden_function;
/// The jobs associated with this parser.
job_list_t my_job_list;
/// The list of blocks
std::vector<std::unique_ptr<block_t>> block_stack;
/// The 'depth' of the fish call stack.
int eval_level = -1;
#if 0
// TODO: Lint says this isn't used (which is true). Should this be removed?
/// Gets a description of the block stack, for debugging.
wcstring block_stack_description() const;
#endif
/// List of profile items
/// These are pointers because we return pointers to them to callers,
/// who may hold them across blocks (which would cause reallocations internal
/// to profile_items)
std::vector<std::unique_ptr<profile_item_t>> profile_items;
// No copying allowed.
parser_t(const parser_t &);
parser_t &operator=(const parser_t &);
/// Adds a job to the beginning of the job list.
void job_add(shared_ptr<job_t> job);
/// Returns the name of the currently evaluated function if we are currently evaluating a
/// function, null otherwise. This is tested by moving down the block-scope-stack, checking
/// every block if it is of type FUNCTION_CALL.
const wchar_t *is_function(size_t idx = 0) const;
/// Helper for stack_trace().
void stack_trace_internal(size_t block_idx, wcstring *out) const;
/// Helper for push_block()
void push_block_int(block_t *b);
public:
/// Get the "principal" parser, whatever that is.
static parser_t &principal_parser();
/// Indicates that execution of all blocks in the principal parser should stop. This is called
/// from signal handlers!
static void skip_all_blocks();
/// Create a parser.
parser_t();
/// Global event blocks.
event_blockage_list_t global_event_blocks;
/// Evaluate the expressions contained in cmd.
///
/// \param cmd the string to evaluate
/// \param io io redirections to perform on all started jobs
/// \param block_type The type of block to push on the block stack
///
/// \return 0 on success, 1 on a parse error.
int eval(wcstring cmd, const io_chain_t &io, enum block_type_t block_type);
/// Evaluate the parsed source ps.
void eval(parsed_source_ref_t ps, const io_chain_t &io, enum block_type_t block_type);
/// Evaluates a node.
/// The node type must be grammar::statement or grammar::job_list.
template <typename T>
int eval_node(parsed_source_ref_t ps, tnode_t<T> node, const io_chain_t &io,
enum block_type_t block_type);
/// Evaluate line as a list of parameters, i.e. tokenize it and perform parameter expansion and
/// cmdsubst execution on the tokens. The output is inserted into output. Errors are ignored.
///
/// \param arg_src String to evaluate as an argument list
/// \param flags Some expand flags to use
/// \param output List to insert output into
static void expand_argument_list(const wcstring &arg_src, expand_flags_t flags,
std::vector<completion_t> *output);
/// Returns a string describing the current parser position in the format 'FILENAME (line
/// LINE_NUMBER): LINE'. Example:
///
/// init.fish (line 127): ls|grep pancake
wcstring current_line();
/// Returns the current line number.
int get_lineno() const;
/// Returns the block at the given index. 0 corresponds to the innermost block. Returns NULL
/// when idx is at or equal to the number of blocks.
const block_t *block_at_index(size_t idx) const;
block_t *block_at_index(size_t idx);
/// Returns the current (innermost) block.
block_t *current_block();
/// Count of blocks.
size_t block_count() const { return block_stack.size(); }
/// Get the list of jobs.
job_list_t &job_list() { return my_job_list; }
// Hackish. In order to correctly report the origin of code with no associated file, we need to
// know whether it's run during initialization or not.
void set_is_within_fish_initialization(bool flag);
/// Pushes a new block created with the given arguments
/// Returns a pointer to the block. The pointer is valid
/// until the call to pop_block()
template <typename BLOCKTYPE, typename... Args>
BLOCKTYPE *push_block(Args &&... args) {
BLOCKTYPE *ret = new BLOCKTYPE(std::forward<Args>(args)...);
this->push_block_int(ret);
return ret;
}
/// Remove the outermost block, asserting it's the given one.
void pop_block(const block_t *b);
/// Return a description of the given blocktype.
const wchar_t *get_block_desc(int block) const;
/// Return the function name for the specified stack frame. Default is one (current frame).
const wchar_t *get_function_name(int level = 1);
/// Removes a job.
bool job_remove(job_t *job);
/// Promotes a job to the front of the list.
void job_promote(job_t *job);
/// Return the job with the specified job id. If id is 0 or less, return the last job used.
job_t *job_get(job_id_t job_id);
/// Returns the job with the given pid.
job_t *job_get_from_pid(pid_t pid) const;
/// Returns a new profile item if profiling is active. The caller should fill it in. The
/// parser_t will clean it up.
profile_item_t *create_profile_item();
void get_backtrace(const wcstring &src, const parse_error_list_t &errors,
wcstring &output) const;
/// Detect errors in the specified string when parsed as an argument list. Returns true if an
/// error occurred.
bool detect_errors_in_argument_list(const wcstring &arg_list_src, wcstring *out_err,
const wchar_t *prefix) const;
/// Tell the parser that the specified function may not be run if not inside of a conditional
/// block. This is to remove some possibilities of infinite recursion.
void forbid_function(const wcstring &function);
/// Undo last call to parser_forbid_function().
void allow_function();
/// Output profiling data to the given filename.
void emit_profiling(const char *path) const;
/// Returns the file currently evaluated by the parser. This can be different than
/// reader_current_filename, e.g. if we are evaulating a function defined in a different file
/// than the one curently read.
const wchar_t *current_filename() const;
/// Return a string representing the current stack trace.
wcstring stack_trace() const;
~parser_t();
};
#endif