The Tor Browser: gfx/harfbuzz/src/hb-blob.cc@b8a032363ba2 (annotated)

gfx/harfbuzz/src/hb-blob.cc@b8a032363ba2 (annotated)

gfx/harfbuzz/src/hb-blob.cc

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /*
  * Copyright © 2009  Red Hat, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
  *
  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Red Hat Author(s): Behdad Esfahbod
  */
 /* http://www.oracle.com/technetwork/articles/servers-storage-dev/standardheaderfiles-453865.html */
 #define _POSIX_C_SOURCE 199309L
 #include "hb-private.hh"
 #include "hb-object-private.hh"
 #ifdef HAVE_SYS_MMAN_H
 #ifdef HAVE_UNISTD_H
 #include <unistd.h>
 #endif /* HAVE_UNISTD_H */
 #include <sys/mman.h>
 #endif /* HAVE_SYS_MMAN_H */
 #include <stdio.h>
 #include <errno.h>
 #ifndef HB_DEBUG_BLOB
 #define HB_DEBUG_BLOB (HB_DEBUG+0)
 #endif
 struct hb_blob_t {
   hb_object_header_t header;
   ASSERT_POD ();
   bool immutable;
   const char *data;
   unsigned int length;
   hb_memory_mode_t mode;
   void *user_data;
   hb_destroy_func_t destroy;
 };
 static bool _try_writable (hb_blob_t *blob);
 static void
 _hb_blob_destroy_user_data (hb_blob_t *blob)
 {
   if (blob->destroy) {
     blob->destroy (blob->user_data);
     blob->user_data = NULL;
     blob->destroy = NULL;
   }
 }
 /**
  * hb_blob_create: (Xconstructor)
  * @data: (array length=length) (closure user_data) (destroy destroy) (scope notified) (transfer none): Pointer to blob data.
  * @length: Length of @data in bytes.
  * @mode: Memory mode for @data.
  * @user_data: Data parameter to pass to @destroy.
  * @destroy: Callback to call when @data is not needed anymore.
  *
  * Creates a new "blob" object wrapping @data.  The @mode parameter is used
  * to negotiate ownership and lifecycle of @data.
  *
  * Return value: New blob, or the empty blob if something failed or if @length is
  * zero.  Destroy with hb_blob_destroy().
  *
  * Since: 1.0
  **/
 hb_blob_t *
 hb_blob_create (const char        *data,
 		unsigned int       length,
 		hb_memory_mode_t   mode,
 		void              *user_data,
 		hb_destroy_func_t  destroy)
 {
   hb_blob_t *blob;
   if (!length || !(blob = hb_object_create<hb_blob_t> ())) {
     if (destroy)
       destroy (user_data);
     return hb_blob_get_empty ();
   }
   blob->data = data;
   blob->length = length;
   blob->mode = mode;
   blob->user_data = user_data;
   blob->destroy = destroy;
   if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
     blob->mode = HB_MEMORY_MODE_READONLY;
     if (!_try_writable (blob)) {
       hb_blob_destroy (blob);
       return hb_blob_get_empty ();
     }
   }
   return blob;
 }
 /**
  * hb_blob_create_sub_blob:
  * @parent: Parent blob.
  * @offset: Start offset of sub-blob within @parent, in bytes.
  * @length: Length of sub-blob.
  *
  * Returns a blob that represents a range of bytes in @parent.  The new
  * blob is always created with %HB_MEMORY_MODE_READONLY, meaning that it
  * will never modify data in the parent blob.  The parent data is not
  * expected to be modified, and will result in undefined behavior if it
  * is.
  *
  * Makes @parent immutable.
  *
  * Return value: New blob, or the empty blob if something failed or if
  * @length is zero or @offset is beyond the end of @parent's data.  Destroy
  * with hb_blob_destroy().
  *
  * Since: 1.0
  **/
 hb_blob_t *
 hb_blob_create_sub_blob (hb_blob_t    *parent,
 			 unsigned int  offset,
 			 unsigned int  length)
 {
   hb_blob_t *blob;
   if (!length || offset >= parent->length)
     return hb_blob_get_empty ();
   hb_blob_make_immutable (parent);
   blob = hb_blob_create (parent->data + offset,
 			 MIN (length, parent->length - offset),
 			 HB_MEMORY_MODE_READONLY,
 			 hb_blob_reference (parent),
 			 (hb_destroy_func_t) hb_blob_destroy);
   return blob;
 }
 /**
  * hb_blob_get_empty:
  *
  * Returns the singleton empty blob.
  *
  * See TODO:link object types for more information.
  *
  * Return value: (transfer full): the empty blob.
  *
  * Since: 1.0
  **/
 hb_blob_t *
 hb_blob_get_empty (void)
 {
   static const hb_blob_t _hb_blob_nil = {
     HB_OBJECT_HEADER_STATIC,
     true, /* immutable */
     NULL, /* data */
 , /* length */
     HB_MEMORY_MODE_READONLY, /* mode */
     NULL, /* user_data */
     NULL  /* destroy */
   };
   return const_cast<hb_blob_t *> (&_hb_blob_nil);
 }
 /**
  * hb_blob_reference: (skip)
  * @blob: a blob.
  *
  * Increases the reference count on @blob.
  *
  * See TODO:link object types for more information.
  *
  * Return value: @blob.
  *
  * Since: 1.0
  **/
 hb_blob_t *
 hb_blob_reference (hb_blob_t *blob)
 {
   return hb_object_reference (blob);
 }
 /**
  * hb_blob_destroy: (skip)
  * @blob: a blob.
  *
  * Descreases the reference count on @blob, and if it reaches zero, destroys
  * @blob, freeing all memory, possibly calling the destroy-callback the blob
  * was created for if it has not been called already.
  *
  * See TODO:link object types for more information.
  *
  * Since: 1.0
  **/
 void
 hb_blob_destroy (hb_blob_t *blob)
 {
   if (!hb_object_destroy (blob)) return;
   _hb_blob_destroy_user_data (blob);
   free (blob);
 }
 /**
  * hb_blob_set_user_data: (skip)
  * @blob: a blob.
  * @key: key for data to set.
  * @data: data to set.
  * @destroy: callback to call when @data is not needed anymore.
  * @replace: whether to replace an existing data with the same key.
  *
  * Return value:
  *
  * Since: 1.0
  **/
 hb_bool_t
 hb_blob_set_user_data (hb_blob_t          *blob,
 		       hb_user_data_key_t *key,
 		       void *              data,
 		       hb_destroy_func_t   destroy,
 		       hb_bool_t           replace)
 {
   return hb_object_set_user_data (blob, key, data, destroy, replace);
 }
 /**
  * hb_blob_get_user_data: (skip)
  * @blob: a blob.
  * @key: key for data to get.
  *
  *
  *
  * Return value: (transfer none):
  *
  * Since: 1.0
  **/
 void *
 hb_blob_get_user_data (hb_blob_t          *blob,
 		       hb_user_data_key_t *key)
 {
   return hb_object_get_user_data (blob, key);
 }
 /**
  * hb_blob_make_immutable:
  * @blob: a blob.
  *
  *
  *
  * Since: 1.0
  **/
 void
 hb_blob_make_immutable (hb_blob_t *blob)
 {
   if (hb_object_is_inert (blob))
     return;
   blob->immutable = true;
 }
 /**
  * hb_blob_is_immutable:
  * @blob: a blob.
  *
  *
  *
  * Return value: TODO
  *
  * Since: 1.0
  **/
 hb_bool_t
 hb_blob_is_immutable (hb_blob_t *blob)
 {
   return blob->immutable;
 }
 /**
  * hb_blob_get_length:
  * @blob: a blob.
  *
  *
  *
  * Return value: the length of blob data in bytes.
  *
  * Since: 1.0
  **/
 unsigned int
 hb_blob_get_length (hb_blob_t *blob)
 {
   return blob->length;
 }
 /**
  * hb_blob_get_data:
  * @blob: a blob.
  * @length: (out):
  *
  *
  *
  * Returns: (transfer none) (array length=length):
  *
  * Since: 1.0
  **/
 const char *
 hb_blob_get_data (hb_blob_t *blob, unsigned int *length)
 {
   if (length)
     *length = blob->length;
   return blob->data;
 }
 /**
  * hb_blob_get_data_writable:
  * @blob: a blob.
  * @length: (out): output length of the writable data.
  *
  * Tries to make blob data writable (possibly copying it) and
  * return pointer to data.
  *
  * Fails if blob has been made immutable, or if memory allocation
  * fails.
  *
  * Returns: (transfer none) (array length=length): Writable blob data,
  * or %NULL if failed.
  *
  * Since: 1.0
  **/
 char *
 hb_blob_get_data_writable (hb_blob_t *blob, unsigned int *length)
 {
   if (!_try_writable (blob)) {
     if (length)
       *length = 0;
     return NULL;
   }
   if (length)
     *length = blob->length;
   return const_cast<char *> (blob->data);
 }
 static hb_bool_t
 _try_make_writable_inplace_unix (hb_blob_t *blob)
 {
 #if defined(HAVE_SYS_MMAN_H) && defined(HAVE_MPROTECT)
   uintptr_t pagesize = -1, mask, length;
   const char *addr;
 #if defined(HAVE_SYSCONF) && defined(_SC_PAGE_SIZE)
   pagesize = (uintptr_t) sysconf (_SC_PAGE_SIZE);
 #elif defined(HAVE_SYSCONF) && defined(_SC_PAGESIZE)
   pagesize = (uintptr_t) sysconf (_SC_PAGESIZE);
 #elif defined(HAVE_GETPAGESIZE)
   pagesize = (uintptr_t) getpagesize ();
 #endif
   if ((uintptr_t) -1L == pagesize) {
     DEBUG_MSG_FUNC (BLOB, blob, "failed to get pagesize: %s", strerror (errno));
     return false;
   }
   DEBUG_MSG_FUNC (BLOB, blob, "pagesize is %lu", (unsigned long) pagesize);
   mask = ~(pagesize-1);
   addr = (const char *) (((uintptr_t) blob->data) & mask);
   length = (const char *) (((uintptr_t) blob->data + blob->length + pagesize-1) & mask)  - addr;
   DEBUG_MSG_FUNC (BLOB, blob,
 		  "calling mprotect on [%p..%p] (%lu bytes)",
 		  addr, addr+length, (unsigned long) length);
   if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE)) {
     DEBUG_MSG_FUNC (BLOB, blob, "mprotect failed: %s", strerror (errno));
     return false;
   }
   blob->mode = HB_MEMORY_MODE_WRITABLE;
   DEBUG_MSG_FUNC (BLOB, blob,
 		  "successfully made [%p..%p] (%lu bytes) writable\n",
 		  addr, addr+length, (unsigned long) length);
   return true;
 #else
   return false;
 #endif
 }
 static bool
 _try_writable_inplace (hb_blob_t *blob)
 {
   DEBUG_MSG_FUNC (BLOB, blob, "making writable inplace\n");
   if (_try_make_writable_inplace_unix (blob))
     return true;
   DEBUG_MSG_FUNC (BLOB, blob, "making writable -> FAILED\n");
   /* Failed to make writable inplace, mark that */
   blob->mode = HB_MEMORY_MODE_READONLY;
   return false;
 }
 static bool
 _try_writable (hb_blob_t *blob)
 {
   if (blob->immutable)
     return false;
   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
     return true;
   if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITABLE && _try_writable_inplace (blob))
     return true;
   if (blob->mode == HB_MEMORY_MODE_WRITABLE)
     return true;
   DEBUG_MSG_FUNC (BLOB, blob, "current data is -> %p\n", blob->data);
   char *new_data;
   new_data = (char *) malloc (blob->length);
   if (unlikely (!new_data))
     return false;
   DEBUG_MSG_FUNC (BLOB, blob, "dupped successfully -> %p\n", blob->data);
   memcpy (new_data, blob->data, blob->length);
   _hb_blob_destroy_user_data (blob);
   blob->mode = HB_MEMORY_MODE_WRITABLE;
   blob->data = new_data;
   blob->user_data = new_data;
   blob->destroy = free;
   return true;
 }

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gfx/harfbuzz/src/hb-blob.cc@b8a032363ba2 (annotated)

gfx/harfbuzz/src/hb-blob.cc