fish-shell/src/autoload.h
ridiculousfish 1e57424011 Thread a parser into function_exists
Since this may autoload, it needs a parser with which to autoload.
2019-05-04 20:20:52 -07:00

91 lines
3.7 KiB
C++

// The classes responsible for autoloading functions and completions.
#ifndef FISH_AUTOLOAD_H
#define FISH_AUTOLOAD_H
#include "config.h" // IWYU pragma: keep
#include "common.h"
#include "env.h"
#include "wutil.h"
#include <cassert>
#include <memory>
#include <unordered_map>
#include <unordered_set>
class autoload_file_cache_t;
class environment_t;
class parser_t;
/// autoload_t is a class that knows how to autoload .fish files from a list of directories. This
/// is used by autoloading functions and completions. It maintains a file cache, which is
/// responsible for potentially cached accesses of files, and then a list of files that have
/// actually been autoloaded. A client may request a file to autoload given a command name, and may
/// be returned a path which it is expected to source.
/// autoload_t does not have any internal locks; it is the responsibility of the caller to lock
/// it.
class autoload_t {
/// The environment variable whose paths we observe.
const wcstring env_var_name_;
/// A map from command to the files we have autoloaded.
std::unordered_map<wcstring, file_id_t> autoloaded_files_;
/// The list of commands that we are currently autoloading.
std::unordered_set<wcstring> current_autoloading_;
/// The autoload cache.
/// This is a unique_ptr because want to change it if the value of our environment variable
/// changes. This is never null (but it may be a cache with no paths).
std::unique_ptr<autoload_file_cache_t> cache_;
public:
/// Construct an autoloader that loads from the paths given by \p env_var_name.
explicit autoload_t(wcstring env_var_name);
autoload_t(autoload_t &&);
~autoload_t();
/// Given a command, get a path to autoload.
/// For example, if the environment variable is 'fish_function_path' and the command is 'foo',
/// this will look for a file 'foo.fish' in one of the directories given by fish_function_path.
/// If there is no such file, OR if the file has been previously resolved and is now unchanged,
/// this will return none. But if the file is either new or changed, this will return the path.
/// After returning a path, the command is marked in-progress until the caller calls
/// mark_autoload_finished() with the same command. Note this does not actually execute any
/// code; it is the caller's responsibility to load the file.
maybe_t<wcstring> resolve_command(const wcstring &cmd, const environment_t &env);
/// Helper to actually perform an autoload.
/// This is a static function because it executes fish script, and so must be called without
/// holding any particular locks.
static void perform_autoload(const wcstring &path, parser_t &parser);
/// Mark that a command previously returned from path_to_autoload is finished autoloading.
void mark_autoload_finished(const wcstring &cmd) {
size_t amt = current_autoloading_.erase(cmd);
assert(amt > 0 && "cmd was not being autoloaded");
(void)amt;
}
/// \return whether a command is currently being autoloaded.
bool autoload_in_progress(const wcstring &cmd) const {
return current_autoloading_.count(cmd) > 0;
}
/// \return whether a command could potentially be autoloaded.
/// This does not actually mark the command as being autoloaded.
bool can_autoload(const wcstring &cmd);
/// \return the names of all commands that have been autoloaded.
wcstring_list_t get_autoloaded_commands() const;
/// Mark that all autoloaded files have been forgotten.
/// Future calls to path_to_autoload() will return previously-returned paths.
void clear() {
// Note there is no reason to invalidate the cache here.
autoloaded_files_.clear();
}
};
#endif