[glib] Drop iconv caching code

[Matthias Clasen <matthiasc src gnome org>]

commit 331e93c3f1ad95cb4add48213613e8eeee8cb386
Author: Colin Walters <walters verbum org>
Date:   Sun Jul 28 00:21:00 2013 +0100

    Drop iconv caching code
    
    This was introduced for Solaris performance theoretically;
    we have never been able to use it on Linux/glibc because
    the UTF-16 BOM state isn't reset.
    
    We have no data about Solaris performance; were some to
    still exist, we could reintroduce the code with an explicit
    check for Solaris, not a check for glibc.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=704999

 configure.ac    |   27 -----
 glib/gconvert.c |  297 -------------------------------------------------------
 2 files changed, 0 insertions(+), 324 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 9443709..943da7f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -434,33 +434,6 @@ AS_IF([ test x"$glib_native_win32" = xyes], [
   fi
 ])
 
-AC_ARG_ENABLE(iconv-cache, 
-              [AS_HELP_STRING([--enable-iconv-cache=@<:@yes/no/auto@:>@],
-                              [cache iconv descriptors [default=auto]])],,
-              [enable_iconv_cache=auto])
-
-AC_MSG_CHECKING([whether to cache iconv descriptors])
-case $enable_iconv_cache in
-  auto)
-    if test $ac_cv_gnu_library_2_1 = yes; then
-      enable_iconv_cache=no
-    else 
-      enable_iconv_cache=yes
-    fi
-  ;;
-  yes|no) 
-  ;;
-  *) AC_MSG_ERROR([Value given to --enable-iconv-cache must be one of yes, no or auto])
-  ;;
-esac
-
-if test $enable_iconv_cache = yes; then
-   AC_DEFINE(NEED_ICONV_CACHE,1,[Do we cache iconv descriptors])
-fi
-
-AC_MSG_RESULT($enable_iconv_cache)
-
-
 dnl
 dnl zlib support
 dnl
diff --git a/glib/gconvert.c b/glib/gconvert.c
index 3320a5e..c28e171 100644
--- a/glib/gconvert.c
+++ b/glib/gconvert.c
@@ -51,11 +51,6 @@
 #include "gunicode.h"
 #include "gfileutils.h"
 
-#ifdef NEED_ICONV_CACHE
-#include "glist.h"
-#include "ghash.h"
-#endif
-
 #include "glibintl.h"
 
 #if defined(USE_LIBICONV_GNU) && !defined (_LIBICONV_H)
@@ -333,296 +328,6 @@ g_iconv_close (GIConv converter)
   return iconv_close (cd);
 }
 
-
-#ifdef NEED_ICONV_CACHE
-
-#define ICONV_CACHE_SIZE   (16)
-
-struct _iconv_cache_bucket {
-  gchar *key;
-  guint32 refcount;
-  gboolean used;
-  GIConv cd;
-};
-
-static GList *iconv_cache_list;
-static GHashTable *iconv_cache;
-static GHashTable *iconv_open_hash;
-static guint iconv_cache_size = 0;
-G_LOCK_DEFINE_STATIC (iconv_cache_lock);
-
-/* caller *must* hold the iconv_cache_lock */
-static void
-iconv_cache_init (void)
-{
-  static gboolean initialized = FALSE;
-  
-  if (initialized)
-    return;
-  
-  iconv_cache_list = 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);
-  
-  initialized = TRUE;
-}
-
-
-/*
- * 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.
- *
- * This assumes ownership of @key.
- *
- * Returns a pointer to the newly allocated cache bucket.
- **/
-static struct _iconv_cache_bucket *
-iconv_cache_bucket_new (gchar *key, GIConv cd)
-{
-  struct _iconv_cache_bucket *bucket;
-  
-  bucket = g_new (struct _iconv_cache_bucket, 1);
-  bucket->key = key;
-  bucket->refcount = 1;
-  bucket->used = TRUE;
-  bucket->cd = cd;
-  
-  g_hash_table_insert (iconv_cache, bucket->key, bucket);
-  
-  /* FIXME: if we sorted the list so items with few refcounts were
-     first, then we could expire them faster in iconv_cache_expire_unused () */
-  iconv_cache_list = g_list_prepend (iconv_cache_list, bucket);
-  
-  iconv_cache_size++;
-  
-  return bucket;
-}
-
-
-/*
- * iconv_cache_bucket_expire:
- * @node: cache bucket's node
- * @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.
- *
- * @node is not a required argument. If @node is not supplied, we
- * search for it ourselves.
- **/
-static void
-iconv_cache_bucket_expire (GList *node, struct _iconv_cache_bucket *bucket)
-{
-  g_hash_table_remove (iconv_cache, bucket->key);
-  
-  if (node == NULL)
-    node = g_list_find (iconv_cache_list, bucket);
-  
-  g_assert (node != NULL);
-  
-  if (node->prev)
-    {
-      node->prev->next = node->next;
-      if (node->next)
-        node->next->prev = node->prev;
-    }
-  else
-    {
-      iconv_cache_list = node->next;
-      if (node->next)
-        node->next->prev = NULL;
-    }
-  
-  g_list_free_1 (node);
-  
-  g_free (bucket->key);
-  g_iconv_close (bucket->cd);
-  g_free (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;
-  GList *node, *next;
-  
-  node = iconv_cache_list;
-  while (node && iconv_cache_size >= ICONV_CACHE_SIZE)
-    {
-      next = node->next;
-      
-      bucket = node->data;
-      if (bucket->refcount == 0)
-        iconv_cache_bucket_expire (node, bucket);
-      
-      node = next;
-    }
-}
-
-static GIConv
-open_converter (const gchar *to_codeset,
-               const gchar *from_codeset,
-               GError     **error)
-{
-  struct _iconv_cache_bucket *bucket;
-  gchar *key, *dyn_key, auto_key[80];
-  GIConv cd;
-  gsize len_from_codeset, len_to_codeset;
-  
-  /* create our key */
-  len_from_codeset = strlen (from_codeset);
-  len_to_codeset = strlen (to_codeset);
-  if (len_from_codeset + len_to_codeset + 2 < sizeof (auto_key))
-    {
-      key = auto_key;
-      dyn_key = NULL;
-    }
-  else
-    key = dyn_key = g_malloc (len_from_codeset + len_to_codeset + 2);
-  memcpy (key, from_codeset, len_from_codeset);
-  key[len_from_codeset] = ':';
-  strcpy (key + len_from_codeset + 1, to_codeset);
-
-  G_LOCK (iconv_cache_lock);
-  
-  /* make sure the cache has been initialized */
-  iconv_cache_init ();
-  
-  bucket = g_hash_table_lookup (iconv_cache, key);
-  if (bucket)
-    {
-      g_free (dyn_key);
-
-      if (bucket->used)
-        {
-          cd = g_iconv_open (to_codeset, from_codeset);
-          if (cd == (GIConv) -1)
-            goto error;
-        }
-      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.)
-          */
-         gsize inbytes_left = 0;
-         gchar *outbuf = NULL;
-         gsize outbytes_left = 0;
-               
-          cd = bucket->cd;
-          bucket->used = TRUE;
-          
-          /* reset the descriptor */
-          g_iconv (cd, NULL, &inbytes_left, &outbuf, &outbytes_left);
-        }
-      
-      bucket->refcount++;
-    }
-  else
-    {
-      cd = g_iconv_open (to_codeset, from_codeset);
-      if (cd == (GIConv) -1) 
-       {
-         g_free (dyn_key);
-         goto error;
-       }
-      
-      iconv_cache_expire_unused ();
-
-      bucket = iconv_cache_bucket_new (dyn_key ? dyn_key : g_strdup (key), cd);
-    }
-  
-  g_hash_table_insert (iconv_open_hash, cd, bucket->key);
-  
-  G_UNLOCK (iconv_cache_lock);
-  
-  return cd;
-  
- error:
-  
-  G_UNLOCK (iconv_cache_lock);
-  
-  /* Something went wrong.  */
-  if (error)
-    {
-      if (errno == EINVAL)
-       g_set_error (error, G_CONVERT_ERROR, G_CONVERT_ERROR_NO_CONVERSION,
-                    _("Conversion from character set '%s' to '%s' is not supported"),
-                    from_codeset, to_codeset);
-      else
-       g_set_error (error, G_CONVERT_ERROR, G_CONVERT_ERROR_FAILED,
-                    _("Could not open converter from '%s' to '%s'"),
-                    from_codeset, to_codeset);
-    }
-  
-  return cd;
-}
-
-static int
-close_converter (GIConv converter)
-{
-  struct _iconv_cache_bucket *bucket;
-  const gchar *key;
-  GIConv cd;
-  
-  cd = converter;
-  
-  if (cd == (GIConv) -1)
-    return 0;
-  
-  G_LOCK (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 (NULL, bucket);
-        }
-    }
-  else
-    {
-      G_UNLOCK (iconv_cache_lock);
-      
-      g_warning ("This iconv context wasn't opened using open_converter");
-      
-      return g_iconv_close (converter);
-    }
-  
-  G_UNLOCK (iconv_cache_lock);
-  
-  return 0;
-}
-
-#else  /* !NEED_ICONV_CACHE */
-
 static GIConv
 open_converter (const gchar *to_codeset,
                const gchar *from_codeset,
@@ -660,8 +365,6 @@ close_converter (GIConv cd)
   return g_iconv_close (cd);  
 }
 
-#endif /* NEED_ICONV_CACHE */
-
 /**
  * g_convert_with_iconv:
  * @str:           the string to convert