Merge branch 'master' into iwyu

1 files changed, 135 insertions, 0 deletions

diff --git a/src/autoload.h b/src/autoload.h
new file mode 100644
index 00000000..610efed0
--- /dev/null
+++ b/src/autoload.h
@@ -0,0 +1,135 @@
+/** \file autoload.h
+
+    The classes responsible for autoloading functions and completions.
+*/
+
+#ifndef FISH_AUTOLOAD_H
+#define FISH_AUTOLOAD_H
+
+#include <pthread.h>
+#include <stddef.h>
+#include <time.h>
+#include <set>
+#include "common.h"
+#include "lru.h"
+
+/** A struct responsible for recording an attempt to access a file. */
+struct file_access_attempt_t
+{
+    time_t mod_time; /** The modification time of the file */
+    time_t last_checked; /** When we last checked the file */
+    bool accessible; /** Whether we believe we could access this file */
+    bool stale; /** Whether the access attempt is stale */
+    int error; /** If we could not access the file, the error code */
+};
+
+file_access_attempt_t access_file(const wcstring &path, int mode);
+
+struct autoload_function_t : public lru_node_t
+{
+    autoload_function_t(const wcstring &key) : lru_node_t(key), access(), is_loaded(false), is_placeholder(false), is_internalized(false) { }
+    file_access_attempt_t access; /** The last access attempt */
+    bool is_loaded; /** Whether we have actually loaded this function */
+    bool is_placeholder; /** Whether we are a placeholder that stands in for "no such function". If this is true, then is_loaded must be false. */
+    bool is_internalized; /** Whether this function came from a builtin "internalized" script */
+};
+
+struct builtin_script_t
+{
+    const wchar_t *name;
+    const char *def;
+};
+
+class env_vars_snapshot_t;
+
+/**
+  A class that represents a path from which we can autoload, and the autoloaded contents.
+ */
+class autoload_t : private lru_cache_t<autoload_function_t>
+{
+private:
+
+    /** Lock for thread safety */
+    pthread_mutex_t lock;
+
+    /** The environment variable name */
+    const wcstring env_var_name;
+
+    /** Builtin script array */
+    const struct builtin_script_t *const builtin_scripts;
+
+    /** Builtin script count */
+    const size_t builtin_script_count;
+
+    /** The path from which we most recently autoloaded */
+    wcstring last_path;
+
+    /** That path, tokenized (split on separators) */
+    wcstring_list_t last_path_tokenized;
+
+    /**
+       A table containing all the files that are currently being
+       loaded. This is here to help prevent recursion.
+    */
+    std::set<wcstring> is_loading_set;
+
+    void remove_all_functions(void)
+    {
+        this->evict_all_nodes();
+    }
+
+    bool locate_file_and_maybe_load_it(const wcstring &cmd, bool really_load, bool reload, const wcstring_list_t &path_list);
+
+    virtual void node_was_evicted(autoload_function_t *node);
+
+    autoload_function_t *get_autoloaded_function_with_creation(const wcstring &cmd, bool allow_eviction);
+
+protected:
+    /** Overridable callback for when a command is removed */
+    virtual void command_removed(const wcstring &cmd) { }
+
+public:
+
+    /** Create an autoload_t for the given environment variable name */
+    autoload_t(const wcstring &env_var_name_var, const builtin_script_t *scripts, size_t script_count);
+
+    /** Destructor */
+    virtual ~autoload_t();
+
+    /**
+       Autoload the specified file, if it exists in the specified path. Do
+       not load it multiple times unless its timestamp changes or
+       parse_util_unload is called.
+
+       Autoloading one file may unload another.
+
+       \param cmd the filename to search for. The suffix '.fish' is always added to this name
+       \param on_unload a callback function to run if a suitable file is found, which has not already been run. unload will also be called for old files which are unloaded.
+       \param reload wheter to recheck file timestamps on already loaded files
+    */
+    int load(const wcstring &cmd, bool reload);
+
+    /** Check whether we have tried loading the given command. Does not do any I/O. */
+    bool has_tried_loading(const wcstring &cmd);
+
+    /**
+       Tell the autoloader that the specified file, in the specified path,
+       is no longer loaded.
+
+       \param cmd the filename to search for. The suffix '.fish' is always added to this name
+       \param on_unload a callback function which will be called before (re)loading a file, may be used to unload the previous file.
+       \return non-zero if the file was removed, zero if the file had not yet been loaded
+    */
+    int unload(const wcstring &cmd);
+
+    /**
+       Unloads all files.
+    */
+    void unload_all();
+
+    /** Check whether the given command could be loaded, but do not load it. */
+    bool can_load(const wcstring &cmd, const env_vars_snapshot_t &vars);
+
+};
+
+#endif