fish-shell/history.cpp

563 lines
14 KiB
C++

/** \file history.c
History functions, part of the user interface.
*/
#include "config.h"
#include <stdlib.h>
#include <stdio.h>
#include <wchar.h>
#include <errno.h>
#include <dirent.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <sys/mman.h>
#include <fcntl.h>
#include <string.h>
#include <time.h>
#include <assert.h>
#include "fallback.h"
#include "util.h"
#include "wutil.h"
#include "history.h"
#include "common.h"
#include "halloc.h"
#include "halloc_util.h"
#include "intern.h"
#include "path.h"
#include "signal.h"
#include "autoload.h"
#include <map>
#include <algorithm>
/** When we rewrite the history, the number of items we keep */
#define HISTORY_SAVE_MAX (1024 * 256)
/** Interval in seconds between automatic history save */
#define SAVE_INTERVAL (5*60)
/** Number of new history entries to add before automatic history save */
#define SAVE_COUNT 5
/* Our LRU cache is used for restricting the amount of history we have, and limiting how long we order it. */
class history_lru_node_t : public lru_node_t {
public:
time_t timestamp;
history_lru_node_t(const history_item_t &item) : lru_node_t(item.str()), timestamp(item.timestamp()) {}
bool write_to_file(FILE *f) const;
};
class history_lru_cache_t : public lru_cache_t<history_lru_node_t> {
protected:
/* Override to delete evicted nodes */
virtual void node_was_evicted(history_lru_node_t *node) {
delete node;
}
public:
history_lru_cache_t(size_t max) : lru_cache_t<history_lru_node_t>(max) { }
/* Function to add a history item */
void add_item(const history_item_t &item) {
/* Skip empty items */
if (item.empty())
return;
/* See if it's in the cache. If it is, update the timestamp. If not, we create a new node and add it. Note that calling get_node promotes the node to the front. */
history_lru_node_t *node = this->get_node(item.str());
if (node != NULL) {
node->timestamp = std::max(node->timestamp, item.timestamp());
} else {
node = new history_lru_node_t(item);
this->add_node(node);
}
}
};
static pthread_mutex_t hist_lock = PTHREAD_MUTEX_INITIALIZER;
static std::map<wcstring, history_t *> histories;
static wcstring history_filename(const wcstring &name, const wcstring &suffix);
/* Unescapes newlines in-place */
static void unescape_newlines(wcstring &str);
/* Escapes newlines in-place */
static void escape_newlines(wcstring &str);
/* Custom deleter for our shared_ptr */
class history_item_data_deleter_t {
private:
const bool free_it;
public:
history_item_data_deleter_t(bool flag) : free_it(flag) { }
void operator()(const wchar_t *data) {
if (free_it)
free((void *)data);
}
};
history_item_t::history_item_t(const wcstring &str) : contents(str), creation_timestamp(time(NULL))
{
}
history_item_t::history_item_t(const wcstring &str, time_t when) : contents(str), creation_timestamp(when)
{
}
bool history_lru_node_t::write_to_file(FILE *f) const {
wcstring escaped = key;
escape_newlines(escaped);
return fwprintf( f, L"# %d\n%ls\n", timestamp, escaped.c_str());
}
history_t & history_t::history_with_name(const wcstring &name) {
/* Note that histories are currently never deleted, so we can return a reference to them without using something like shared_ptr */
scoped_lock locker(hist_lock);
history_t *& current = histories[name];
if (current == NULL)
current = new history_t(name);
return *current;
}
history_t::history_t(const wcstring &pname) :
name(pname),
mmap_start(NULL),
mmap_length(0),
save_timestamp(0),
loaded_old(false)
{
pthread_mutex_init(&lock, NULL);
}
history_t::~history_t()
{
pthread_mutex_destroy(&lock);
}
void history_t::add(const wcstring &str)
{
scoped_lock locker(lock);
new_items.push_back(history_item_t(str.c_str(), true));
/* This might be a good candidate for moving to a background thread */
if((time(0) > save_timestamp + SAVE_INTERVAL) || (new_items.size() >= SAVE_COUNT))
this->save_internal();
}
history_item_t history_t::item_at_index(size_t idx) {
scoped_lock locker(lock);
/* 0 is considered an invalid index */
assert(idx > 0);
idx--;
/* idx=0 corresponds to last item in new_items */
size_t new_item_count = new_items.size();
if (idx < new_item_count) {
return new_items.at(new_item_count - idx - 1);
}
/* Now look in our old items */
idx -= new_item_count;
load_old_if_needed();
size_t old_item_count = old_item_offsets.size();
if (idx < old_item_count) {
/* idx=0 corresponds to last item in old_item_offsets */
size_t offset = old_item_offsets.at(old_item_count - idx - 1);
return history_t::decode_item(mmap_start + offset, mmap_length - offset);
}
/* Index past the valid range, so return an empty history item */
return history_item_t(wcstring(), 0);
}
history_item_t history_t::decode_item(const char *begin, size_t len)
{
const char *pos = begin, *end = begin + len;
int was_backslash = 0;
wcstring output;
time_t timestamp = 0;
int first_char = 1;
bool timestamp_mode = false;
while( 1 )
{
wchar_t c;
mbstate_t state;
bzero(&state, sizeof state);
size_t res;
res = mbrtowc( &c, pos, end-pos, &state );
if( res == (size_t)-1 )
{
pos++;
continue;
}
else if( res == (size_t)-2 )
{
break;
}
else if( res == (size_t)0 )
{
pos++;
continue;
}
pos += res;
if( c == L'\n' )
{
if( timestamp_mode )
{
const wchar_t *time_string = output.c_str();
while( *time_string && !iswdigit(*time_string))
time_string++;
errno=0;
if( *time_string )
{
time_t tm;
wchar_t *end;
errno = 0;
tm = (time_t)wcstol( time_string, &end, 10 );
if( tm && !errno && !*end )
{
timestamp = tm;
}
}
output.clear();
timestamp_mode = 0;
continue;
}
if( !was_backslash )
break;
}
if( first_char )
{
if( c == L'#' )
timestamp_mode = 1;
}
first_char = 0;
output.push_back(c);
was_backslash = ( (c == L'\\') && !was_backslash);
}
unescape_newlines(output);
return history_item_t(output, timestamp);
}
void history_t::populate_from_mmap(void)
{
const char *begin = mmap_start;
const char *end = begin + mmap_length;
const char *pos;
int ignore_newline = 0;
int do_push = 1;
for( pos = begin; pos <end; pos++ )
{
if( do_push )
{
ignore_newline = *pos == '#';
/* Need to unique-ize */
old_item_offsets.push_back(pos - begin);
do_push = 0;
}
switch( *pos )
{
case '\\':
{
pos++;
break;
}
case '\n':
{
if( ignore_newline )
{
ignore_newline = 0;
}
else
{
do_push = 1;
}
break;
}
}
}
}
void history_t::load_old_if_needed(void)
{
if (loaded_old) return;
loaded_old = true;
int fd;
int ok=0;
signal_block();
wcstring filename = history_filename(name, L"");
if( ! filename.empty() )
{
if( ( fd = wopen( filename.c_str(), O_RDONLY ) ) > 0 )
{
off_t len = lseek( fd, 0, SEEK_END );
if( len != (off_t)-1)
{
mmap_length = (size_t)len;
if( lseek( fd, 0, SEEK_SET ) == 0 )
{
if( (mmap_start = (char *)mmap( 0, mmap_length, PROT_READ, MAP_PRIVATE, fd, 0 )) != MAP_FAILED )
{
ok = 1;
this->populate_from_mmap();
}
}
}
close( fd );
}
}
signal_unblock();
}
bool history_search_t::go_forwards() {
/* Pop the top index (if more than one) and return if we have any left */
if (prev_matches.size() > 1) {
prev_matches.pop_back();
return true;
}
return false;
}
bool history_search_t::go_backwards() {
/* Backwards means increasing our index */
const size_t max_idx = (size_t)(-1);
size_t idx = 0;
if (! prev_matches.empty())
idx = prev_matches.back().first;
if (idx == max_idx)
return false;
while (++idx < max_idx) {
const history_item_t item = history->item_at_index(idx);
/* We're done if it's empty */
if (item.empty()) {
return false;
}
/* Look for a term that matches and that we haven't seen before */
if (item.matches_search(term) && ! match_already_made(item.str())) {
prev_matches.push_back(prev_match_t(idx, item.str()));
return true;
}
}
return false;
}
/** Goes to the end (forwards) */
void history_search_t::go_to_end(void) {
prev_matches.clear();
}
/** Returns if we are at the end, which is where we start. */
bool history_search_t::is_at_end(void) const {
return prev_matches.empty();
}
/** Goes to the beginning (backwards) */
void history_search_t::go_to_beginning(void) {
/* Just go backwards as far as we can */
while (go_backwards())
;
}
wcstring history_search_t::current_item() const {
assert(! prev_matches.empty());
return prev_matches.back().second;
}
bool history_search_t::match_already_made(const wcstring &match) const {
for (std::deque<prev_match_t>::const_iterator iter = prev_matches.begin(); iter != prev_matches.end(); iter++) {
if (iter->second == match)
return true;
}
return false;
}
static void replace_all(wcstring &str, const wchar_t *needle, const wchar_t *replacement)
{
size_t needle_len = wcslen(needle);
size_t offset = 0;
while((offset = str.find(needle, offset)) != wcstring::npos)
{
str.replace(offset, needle_len, replacement);
offset += needle_len;
}
}
static void unescape_newlines(wcstring &str)
{
/* Replace instances of backslash + newline with just the newline */
replace_all(str, L"\\\n", L"\n");
}
static void escape_newlines(wcstring &str)
{
/* Replace instances of newline with backslash + newline with newline */
replace_all(str, L"\\\n", L"\n");
/* If the string ends with a backslash, we'll combine it with the next line. Hack around that by appending a newline. */
if (! str.empty() && str.at(str.size() - 1) == L'\\')
str.push_back('\n');
}
static wcstring history_filename(const wcstring &name, const wcstring &suffix)
{
wcstring path;
if (! path_get_config(path))
return L"";
wcstring result = path;
result.append(L"/");
result.append(name);
result.append(L"_history");
result.append(suffix);
return result;
}
/** Save the specified mode to file */
void history_t::save_internal()
{
/* This must be called while locked */
/* Nothing to do if there's no new items */
if (new_items.empty())
return;
bool ok = true;
signal_block();
wcstring tmp_name = history_filename(name, L".tmp");
if( ! tmp_name.empty() )
{
FILE *out;
if( (out=wfopen( tmp_name.c_str(), "w" ) ) )
{
/* Load old */
load_old_if_needed();
/* Make an LRU cache to save only the last N elements */
history_lru_cache_t lru(HISTORY_SAVE_MAX);
/* Insert old items in, from old to new */
for (std::vector<size_t>::iterator iter = old_item_offsets.begin(); iter != old_item_offsets.end(); iter++) {
size_t offset = *iter;
history_item_t item = history_t::decode_item(mmap_start + offset, mmap_length - offset);
lru.add_item(item);
}
/* Insert new items */
for (std::vector<history_item_t>::iterator iter = new_items.begin(); iter != new_items.end(); iter++) {
lru.add_item(*iter);
}
/* Write them out */
for (history_lru_cache_t::iterator iter = lru.begin(); iter != lru.end(); iter++) {
if (! (*iter)->write_to_file(out)) {
ok = false;
break;
}
}
if( fclose( out ) || !ok )
{
/*
This message does not have high enough priority to
be shown by default.
*/
debug( 2, L"Error when writing history file" );
}
else
{
wcstring new_name = history_filename(name, wcstring());
wrename(tmp_name.c_str(), new_name.c_str());
}
}
}
if( ok )
{
/* Our history has been written to the file, so clear our state so we can re-reference the file. */
if (mmap_start != NULL && mmap_start != MAP_FAILED) {
munmap((void *)mmap_start, mmap_length);
}
mmap_start = 0;
mmap_length = 0;
loaded_old = false;
new_items.clear();
old_item_offsets.clear();
save_timestamp=time(0);
}
signal_unblock();
}
void history_t::save(void) {
scoped_lock locker(lock);
this->save_internal();
}
void history_init()
{
}
void history_destroy()
{
/* Save all histories */
for (std::map<wcstring, history_t *>::iterator iter = histories.begin(); iter != histories.end(); iter++) {
iter->second->save();
}
}
void history_sanity_check()
{
/*
No sanity checking implemented yet...
*/
}