fish-shell/autoload.h
2012-01-25 18:40:08 -08:00

138 lines
4.4 KiB
C++

/** \file autoload.h
The classes responsible for autoloading functions and completions.
*/
#ifndef FISH_AUTOLOAD_H
#define FISH_AUTOLOAD_H
#include <wchar.h>
#include <map>
#include <set>
#include <list>
#include "common.h"
extern const time_t kFishDefaultStalenessInterval;
/** 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 */
};
class file_access_node_t;
/** A predicate to compare dereferenced pointers */
struct dereference_less_t {
template <typename ptr_t>
bool operator()(ptr_t p1, ptr_t p2) const { return *p1 < *p2; }
};
file_access_attempt_t access_file(const wcstring &path, int mode);
/** A class responsible for tracking accesses to files, including auto-expiration. */
class access_tracker_t {
private:
file_access_node_t * while_locked_find_node(const wcstring &str) const;
void vacuum_one_node(void);
void promote_node(file_access_node_t *);
file_access_attempt_t attempt_access(const wcstring& path) const;
unsigned int node_count;
typedef std::set<file_access_node_t *, dereference_less_t> access_set_t;
access_set_t access_set;
file_access_node_t *mouth;
/* Lock for thread safety */
pthread_mutex_t lock;
/** How long until a file access attempt is considered stale. */
const time_t stale_interval;
/** Mode for waccess calls */
const int mode;
public:
/** Constructor, that takes a staleness interval */
access_tracker_t(time_t stale, int the_mode);
/** Destructor */
~access_tracker_t();
/** Attempt to access the given file, if the last cached access is stale. Caches and returns the access attempt. */
file_access_attempt_t access_file(const wcstring &path);
/** Returns whether there is a cached access (even if stale), without touching the disk; if the result is true, return by reference that access attempt. */
bool access_file_only_cached(const wcstring &path, file_access_attempt_t &attempt);
};
class lru_node_t {
friend class lru_cache_impl_t;
/** Our linked list pointer */
lru_node_t *prev, *next;
public:
/** The key used to look up in the cache */
const wcstring key;
/** Constructor */
lru_node_t(const wcstring &keyVar) : prev(NULL), next(NULL), key(keyVar) { }
bool operator<(const lru_node_t &other) const { return key < other.key; }
};
class lru_cache_impl_t {
private:
void promote_node(lru_node_t *);
void evict_node(lru_node_t *node);
void evict_last_node(void);
/** Count of nodes */
unsigned int node_count;
/** The set of nodes */
typedef std::set<lru_node_t *, dereference_less_t> node_set_t;
node_set_t node_set;
/** Head of the linked list */
lru_node_t mouth;
protected:
/** Overridable callback for when a node is evicted */
virtual void node_was_evicted(lru_node_t *node);
public:
/** Constructor */
lru_cache_impl_t();
/** Returns the node for a given key, or NULL */
lru_node_t *get_node(const wcstring &key);
/** Evicts the node for a given key, returning true if a node was evicted. */
bool evict_node(const wcstring &key);
/** Adds a node under the given key. Returns true if the node was added, false if the node was not because a node with that key is already in the set. */
bool add_node(lru_node_t *node);
/** Evicts all nodes */
void evict_all_nodes(void);
};
/** Template cover to avoid casting */
template<class node_type_t>
class lru_cache_t : public lru_cache_impl_t {
public:
node_type_t *get_node(const wcstring &key) { return static_cast<node_type_t>(lru_cache_impl_t::get_node(key)); }
bool add_node(node_type_t *node) { return lru_cache_impl_t::add_node(node); }
protected:
virtual void node_was_evicted(lru_node_t *node) { this->node_was_evicted(static_cast<node_type_t *>(node)); }
virtual void node_was_evicted(node_type_t *node) { }
};
#endif