[pango/harfbuzz-ng: 32/57] [HB] Simplify sub-blob support
- From: Behdad Esfahbod <behdad src gnome org>
- To: svn-commits-list gnome org
- Cc:
- Subject: [pango/harfbuzz-ng: 32/57] [HB] Simplify sub-blob support
- Date: Tue, 4 Aug 2009 20:04:03 +0000 (UTC)
commit da2a76270a0109111b465ec6ae0041ec09a2b554
Author: Behdad Esfahbod <behdad behdad org>
Date: Mon Aug 3 21:27:08 2009 -0400
[HB] Simplify sub-blob support
pango/opentype/hb-blob.c | 172 +++++++++++++++++----------------------------
pango/opentype/hb-blob.h | 14 +++--
2 files changed, 74 insertions(+), 112 deletions(-)
---
diff --git a/pango/opentype/hb-blob.c b/pango/opentype/hb-blob.c
index 74ddb92..590dd79 100644
--- a/pango/opentype/hb-blob.c
+++ b/pango/opentype/hb-blob.c
@@ -31,13 +31,14 @@
#include <unistd.h>
#include <sys/mman.h>
+/* XXX Not thread-safe */
+
struct _hb_blob_t {
hb_reference_count_t ref_count;
- hb_blob_t *parent;
+ hb_reference_count_t lock;
const char *data;
- unsigned int offset;
unsigned int length;
hb_memory_mode_t mode;
@@ -47,12 +48,11 @@ struct _hb_blob_t {
static hb_blob_t _hb_blob_nil = {
HB_REFERENCE_COUNT_INVALID, /* ref_count */
- NULL, /* parent */
+ HB_REFERENCE_COUNT_INVALID, /* lock */
NULL, /* data */
- 0, /* offset */
0, /* length */
- HB_MEMORY_MODE_READONLY, /* mode */
+ HB_MEMORY_MODE_READONLY_NEVER_DUPLICATE, /* mode */
NULL, /* destroy */
NULL /* user_data */
@@ -62,8 +62,6 @@ static void
_hb_blob_destroy_user_data (hb_blob_t *blob)
{
if (blob->destroy) {
- if (blob->parent == blob->user_data)
- blob->parent = NULL;
blob->destroy (blob->user_data);
blob->destroy = NULL;
blob->user_data = NULL;
@@ -71,42 +69,10 @@ _hb_blob_destroy_user_data (hb_blob_t *blob)
}
static void
-_hb_blob_nullify (hb_blob_t *blob)
-{
- _hb_blob_destroy_user_data (blob);
- blob->data = NULL;
- blob->offset = 0;
- blob->length = 0;
-}
-
-static void
-_hb_blob_sync_parent_mode (hb_blob_t *blob)
+_hb_blob_unlock_and_destroy (hb_blob_t *blob)
{
- if (blob->parent) {
- if (blob->mode != HB_MEMORY_MODE_WRITEABLE && hb_blob_is_writeable (blob->parent))
- blob->mode = HB_MEMORY_MODE_WRITEABLE;
- }
-}
-
-static void
-_hb_blob_sync_parent_data (hb_blob_t *blob)
-{
- if (blob->parent) {
- const char *pdata;
- unsigned int plength;
-
- pdata = hb_blob_get_data (blob->parent, &plength);
-
- if (pdata != blob->data) {
- if (blob->offset >= plength) {
- /* nothing left */
- _hb_blob_nullify (blob);
- } else {
- blob->data = pdata;
- blob->length = MIN (blob->length, plength - blob->offset);
- }
- }
- }
+ hb_blob_unlock (blob);
+ hb_blob_destroy (blob);
}
hb_blob_t *
@@ -124,8 +90,9 @@ hb_blob_create (const char *data,
return &_hb_blob_nil;
}
+ HB_REFERENCE_COUNT_INIT (blob->lock, 0);
+
blob->data = data;
- blob->offset = 0;
blob->length = length;
blob->mode = mode;
@@ -134,7 +101,10 @@ hb_blob_create (const char *data,
if (blob->mode == HB_MEMORY_MODE_DUPLICATE) {
blob->mode = HB_MEMORY_MODE_READONLY;
- hb_blob_make_writeable (blob);
+ if (!hb_blob_try_writeable (blob)) {
+ hb_blob_destroy (blob);
+ return &_hb_blob_nil;
+ }
}
return blob;
@@ -146,22 +116,20 @@ hb_blob_create_sub_blob (hb_blob_t *parent,
unsigned int length)
{
hb_blob_t *blob;
+ const char *pdata;
- if (!length || !HB_OBJECT_DO_CREATE (blob))
+ if (!length || offset >= parent->length || !HB_OBJECT_DO_CREATE (blob))
return &_hb_blob_nil;
- blob->parent = parent; /* we keep the ref in user_data */
+ pdata = hb_blob_lock (parent);
- blob->data = parent->data + 1; /* make sure they're not equal */
- blob->offset = offset;
- blob->length = length;
+ blob->data = pdata + offset;
+ blob->length = MIN (length, parent->length - offset);
blob->mode = parent->mode;
- blob->destroy = (hb_destroy_func_t) hb_blob_destroy;
+ blob->destroy = (hb_destroy_func_t) _hb_blob_unlock_and_destroy;
blob->user_data = hb_blob_reference (parent);
- _hb_blob_sync_parent_data (blob);
-
return blob;
}
@@ -193,93 +161,83 @@ hb_blob_destroy (hb_blob_t *blob)
free (blob);
}
+unsigned int
+hb_blob_get_length (hb_blob_t *blob)
+{
+ return blob->length;
+}
+
const char *
-hb_blob_get_data (hb_blob_t *blob,
- unsigned int *length)
+hb_blob_lock (hb_blob_t *blob)
{
- _hb_blob_sync_parent_data (blob);
+ if (!HB_OBJECT_IS_INERT (blob))
+ (void) _hb_reference_count_inc (blob->lock);
- if (length)
- *length = blob->length;
+ return blob->data;
+}
- return blob->data + blob->offset;
+void
+hb_blob_unlock (hb_blob_t *blob)
+{
+ if (!HB_OBJECT_IS_INERT (blob)) {
+ int old_lock = _hb_reference_count_inc (blob->lock);
+ assert (old_lock > 0);
+ }
}
hb_bool_t
hb_blob_is_writeable (hb_blob_t *blob)
{
- _hb_blob_sync_parent_mode (blob);
-
return blob->mode == HB_MEMORY_MODE_WRITEABLE;
}
hb_bool_t
hb_blob_try_writeable_inplace (hb_blob_t *blob)
{
- if (HB_OBJECT_IS_INERT (blob))
- return FALSE;
-
- _hb_blob_sync_parent_mode (blob);
-
if (blob->mode == HB_MEMORY_MODE_READONLY_MAY_MAKE_WRITEABLE) {
- _hb_blob_sync_parent_data (blob);
+ int pagesize;
+ unsigned int length;
+ const char *addr;
- if (blob->length) {
- int pagesize;
- unsigned int length;
- const char *addr;
+ pagesize = sysconf(_SC_PAGE_SIZE);
+ if (-1 == pagesize)
+ return FALSE;
- pagesize = sysconf(_SC_PAGE_SIZE);
- if (-1 == pagesize)
- return FALSE;
+ addr = (const char *) (((size_t) blob->data) & pagesize);
+ length = (const char *) (((size_t) blob->data + blob->length + pagesize-1) & pagesize) - addr;
+ if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE))
+ return FALSE;
- addr = (const char *) (((size_t) blob->data + blob->offset) & pagesize);
- length = (const char *) (((size_t) blob->data + blob->offset + blob->length + pagesize-1) & pagesize) - addr;
- if (-1 == mprotect ((void *) addr, length, PROT_READ | PROT_WRITE))
- return FALSE;
- }
blob->mode = HB_MEMORY_MODE_WRITEABLE;
}
return blob->mode == HB_MEMORY_MODE_WRITEABLE;
}
-/* DANGER: May rebase or nullify */
-void
-hb_blob_make_writeable (hb_blob_t *blob)
+hb_bool_t
+hb_blob_try_writeable (hb_blob_t *blob)
{
- if (HB_OBJECT_IS_INERT (blob))
- return;
-
- _hb_blob_sync_parent_mode (blob);
-
if (blob->mode == HB_MEMORY_MODE_READONLY_NEVER_DUPLICATE)
- {
- _hb_blob_nullify (blob);
- }
- else if (blob->mode == HB_MEMORY_MODE_READONLY)
+ return FALSE;
+
+ if (blob->mode == HB_MEMORY_MODE_READONLY)
{
char *new_data;
- _hb_blob_sync_parent_data (blob);
-
- if (blob->length) {
- new_data = malloc (blob->length);
- if (new_data)
- memcpy (new_data, blob->data + blob->offset, blob->length);
+ if (HB_REFERENCE_COUNT_HAS_REFERENCE (blob->lock))
+ return FALSE;
+ new_data = malloc (blob->length);
+ if (new_data) {
+ memcpy (new_data, blob->data, blob->length);
+ blob->data = new_data;
+ blob->mode = HB_MEMORY_MODE_WRITEABLE;
_hb_blob_destroy_user_data (blob);
-
- if (!new_data) {
- _hb_blob_nullify (blob);
- } else {
- blob->data = new_data;
- blob->offset = 0;
- }
- }
-
- blob->mode = HB_MEMORY_MODE_WRITEABLE;
+ return TRUE;
+ } else
+ return FALSE;
}
- else
+
+ return
hb_blob_try_writeable_inplace (blob);
}
diff --git a/pango/opentype/hb-blob.h b/pango/opentype/hb-blob.h
index 4ea5620..193da1d 100644
--- a/pango/opentype/hb-blob.h
+++ b/pango/opentype/hb-blob.h
@@ -65,9 +65,14 @@ hb_blob_get_reference_count (hb_blob_t *blob);
void
hb_blob_destroy (hb_blob_t *blob);
+unsigned int
+hb_blob_get_length (hb_blob_t *blob);
+
const char *
-hb_blob_get_data (hb_blob_t *blob,
- unsigned int *length);
+hb_blob_lock (hb_blob_t *blob);
+
+void
+hb_blob_unlock (hb_blob_t *blob);
hb_bool_t
hb_blob_is_writeable (hb_blob_t *blob);
@@ -75,9 +80,8 @@ hb_blob_is_writeable (hb_blob_t *blob);
hb_bool_t
hb_blob_try_writeable_inplace (hb_blob_t *blob);
-/* DANGER: May rebase or nullify */
-void
-hb_blob_make_writeable (hb_blob_t *blob);
+hb_bool_t
+hb_blob_try_writeable (hb_blob_t *blob);
HB_END_DECLS
[
Date Prev][
Date Next] [
Thread Prev][
Thread Next]
[
Thread Index]
[
Date Index]
[
Author Index]