/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
* Authors: Jeffrey Stedfast <fejj@ximian.com>
*
* Copyright 2003 Ximian, Inc. (www.ximian.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Street #330, Boston, MA 02111-1307, USA.
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <glib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include "e-util/e-memory.h"
#include "camel/camel-charset-map.h"
#include "camel-iconv.h"
#define ICONV_CACHE_SIZE (16)
struct _iconv_cache_bucket {
struct _iconv_cache_bucket *next;
struct _iconv_cache_bucket *prev;
guint32 refcount;
gboolean used;
iconv_t cd;
char *key;
};
static EMemChunk *cache_chunk;
static struct _iconv_cache_bucket *iconv_cache_buckets;
static GHashTable *iconv_cache;
static GHashTable *iconv_open_hash;
static unsigned int iconv_cache_size = 0;
#ifdef G_THREADS_ENABLED
static GStaticMutex iconv_cache_lock = G_STATIC_MUTEX_INIT;
#define ICONV_CACHE_LOCK() g_static_mutex_lock (&iconv_cache_lock)
#define ICONV_CACHE_UNLOCK() g_static_mutex_unlock (&iconv_cache_lock)
#else
#define ICONV_CACHE_LOCK()
#define ICONV_CACHE_UNLOCK()
#endif /* G_THREADS_ENABLED */
/* caller *must* hold the iconv_cache_lock to call any of the following functions */
/**
* iconv_cache_bucket_new:
* @key: cache key
* @cd: iconv descriptor
*
* Creates a new cache bucket, inserts it into the cache and
* increments the cache size.
*
* Returns a pointer to the newly allocated cache bucket.
**/
static struct _iconv_cache_bucket *
iconv_cache_bucket_new (const char *key, iconv_t cd)
{
struct _iconv_cache_bucket *bucket;
bucket = e_memchunk_alloc (cache_chunk);
bucket->next = NULL;
bucket->prev = NULL;
bucket->key = g_strdup (key);
bucket->refcount = 1;
bucket->used = TRUE;
bucket->cd = cd;
g_hash_table_insert (iconv_cache, bucket->key, bucket);
/* FIXME: Since iconv_cache_expire_unused() traverses the list
from head to tail, perhaps it might be better to append new
nodes rather than prepending? This way older cache buckets
expire first? */
bucket->next = iconv_cache_buckets;
iconv_cache_buckets = bucket;
iconv_cache_size++;
return bucket;
}
/**
* iconv_cache_bucket_expire:
* @bucket: cache bucket
*
* Expires a single cache bucket @bucket. This should only ever be
* called on a bucket that currently has no used iconv descriptors
* open.
**/
static void
iconv_cache_bucket_expire (struct _iconv_cache_bucket *bucket)
{
g_hash_table_remove (iconv_cache, bucket->key);
if (bucket->prev) {
bucket->prev->next = bucket->next;
if (bucket->next)
bucket->next->prev = bucket->prev;
} else {
iconv_cache_buckets = bucket->next;
if (bucket->next)
bucket->next->prev = NULL;
}
g_free (bucket->key);
iconv_close (bucket->cd);
e_memchunk_free (cache_chunk, bucket);
iconv_cache_size--;
}
/**
* iconv_cache_expire_unused:
*
* Expires as many unused cache buckets as it needs to in order to get
* the total number of buckets < ICONV_CACHE_SIZE.
**/
static void
iconv_cache_expire_unused (void)
{
struct _iconv_cache_bucket *bucket, *next;
bucket = iconv_cache_buckets;
while (bucket && iconv_cache_size >= ICONV_CACHE_SIZE) {
next = bucket->next;
if (bucket->refcount == 0)
iconv_cache_bucket_expire (bucket);
bucket = next;
}
}
void
camel_iconv_shutdown (void)
{
struct _iconv_cache_bucket *bucket, *next;
bucket = iconv_cache_buckets;
while (bucket) {
next = bucket->next;
g_free (bucket->key);
g_iconv_close (bucket->cd);
e_memchunk_free (cache_chunk, bucket);
bucket = next;
}
g_hash_table_destroy (iconv_cache);
g_hash_table_destroy (iconv_open_hash);
e_memchunk_destroy (cache_chunk);
}
/**
* camel_iconv_init:
*
* Initialize Camel's iconv cache. This *MUST* be called before any
* camel-iconv interfaces will work correctly.
**/
void
camel_iconv_init (void)
{
static int initialized = FALSE;
if (initialized)
return;
iconv_cache_buckets = NULL;
iconv_cache = g_hash_table_new (g_str_hash, g_str_equal);
iconv_open_hash = g_hash_table_new (g_direct_hash, g_direct_equal);
cache_chunk = e_memchunk_new (ICONV_CACHE_SIZE, sizeof (struct _iconv_cache_bucket));
initialized = TRUE;
}
/**
* camel_iconv_open:
* @to: charset to convert to
* @from: charset to convert from
*
* Allocates a coversion descriptor suitable for converting byte
* sequences from charset @from to charset @to. The resulting
* descriptor can be used with iconv (or the camel_iconv wrapper) any
* number of times until closed using camel_iconv_close.
*
* Returns a new conversion descriptor for use with iconv on success
* or (iconv_t) -1 on fail as well as setting an appropriate errno
* value.
**/
iconv_t
camel_iconv_open (const char *to, const char *from)
{
struct _iconv_cache_bucket *bucket;
iconv_t cd;
char *key;
if (from == NULL || to == NULL) {
errno = EINVAL;
return (iconv_t) -1;
}
if (!strcasecmp (from, "x-unknown"))
from = camel_charset_locale_name ();
/* Even tho g_iconv_open will find the appropriate charset
* format(s) for the to/from charset strings, we still convert
* them to their canonical format here so that our key is in a
* standard format */
from = camel_charset_canonical_name (from);
to = camel_charset_canonical_name (to);
key = g_alloca (strlen (from) + strlen (to) + 2);
sprintf (key, "%s:%s", from, to);
ICONV_CACHE_LOCK ();
bucket = g_hash_table_lookup (iconv_cache, key);
if (bucket) {
if (bucket->used) {
cd = g_iconv_open (to, from);
if (cd == (iconv_t) -1)
goto exception;
} else {
/* Apparently iconv on Solaris <= 7 segfaults if you pass in
* NULL for anything but inbuf; work around that. (NULL outbuf
* or NULL *outbuf is allowed by Unix98.)
*/
size_t inleft = 0, outleft = 0;
char *outbuf = NULL;
cd = bucket->cd;
bucket->used = TRUE;
/* reset the descriptor */
g_iconv (cd, NULL, &inleft, &outbuf, &outleft);
}
bucket->refcount++;
} else {
cd = g_iconv_open (to, from);
if (cd == (iconv_t) -1)
goto exception;
iconv_cache_expire_unused ();
bucket = iconv_cache_bucket_new (key, cd);
}
g_hash_table_insert (iconv_open_hash, cd, bucket->key);
ICONV_CACHE_UNLOCK ();
return cd;
exception:
ICONV_CACHE_UNLOCK ();
if (errno == EINVAL)
g_warning ("Conversion from '%s' to '%s' is not supported", from, to);
else
g_warning ("Could not open converter from '%s' to '%s': %s",
from, to, g_strerror (errno));
return cd;
}
/**
* camel_iconv:
* @cd: conversion descriptor
* @inbuf: address of input buffer
* @inleft: input bytes left
* @outbuf: address of output buffer
* @outleft: output bytes left
*
* Read `man 3 iconv`
**/
size_t
camel_iconv (iconv_t cd, const char **inbuf, size_t *inleft, char **outbuf, size_t *outleft)
{
return iconv (cd, inbuf, inleft, outbuf, outleft);
}
/**
* camel_iconv_close:
* @cd: iconv conversion descriptor
*
* Closes the iconv descriptor @cd.
*
* Returns 0 on success or -1 on fail as well as setting an
* appropriate errno value.
**/
int
camel_iconv_close (iconv_t cd)
{
struct _iconv_cache_bucket *bucket;
const char *key;
if (cd == (iconv_t) -1)
return 0;
ICONV_CACHE_LOCK ();
key = g_hash_table_lookup (iconv_open_hash, cd);
if (key) {
g_hash_table_remove (iconv_open_hash, cd);
bucket = g_hash_table_lookup (iconv_cache, key);
g_assert (bucket);
bucket->refcount--;
if (cd == bucket->cd)
bucket->used = FALSE;
else
g_iconv_close (cd);
if (!bucket->refcount && iconv_cache_size > ICONV_CACHE_SIZE) {
/* expire this cache bucket */
iconv_cache_bucket_expire (bucket);
}
} else {
ICONV_CACHE_UNLOCK ();
g_warning ("This iconv context wasn't opened using camel_iconv_open()");
return g_iconv_close (cd);
}
ICONV_CACHE_UNLOCK ();
return 0;
}
