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Merge pull request #3398 from harfbuzz/buffer-verify 

Add HB_BUFFER_FLAG_VERIFY
This commit is contained in:
Behdad Esfahbod 2022-02-12 15:06:47 -06:00 committed by GitHub
parent b3f8288cca b47b3b9972
commit b263371b09
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
12 changed files with 495 additions and 369 deletions
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1
src/Makefile.sources
View File

@ -25,6 +25,7 @@ HB_BASE_sources = \
hb-blob.cc \
hb-blob.hh \
hb-buffer-serialize.cc \
hb-buffer-verify.cc \
hb-buffer.cc \
hb-buffer.hh \
hb-cache.hh \

1
src/harfbuzz.cc
View File

@ -2,6 +2,7 @@
#include "hb-aat-map.cc"
#include "hb-blob.cc"
#include "hb-buffer-serialize.cc"
#include "hb-buffer-verify.cc"
#include "hb-buffer.cc"
#include "hb-common.cc"
#include "hb-draw.cc"

421
src/hb-buffer-verify.cc Normal file
View File

@ -0,0 +1,421 @@
/*
* Copyright © 2022 Behdad Esfahbod
*
* 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.
*
* Google Author(s): Behdad Esfahbod
*/
#include "hb.hh"
#ifndef HB_NO_BUFFER_VERIFY
#include "hb-buffer.hh"
#define BUFFER_VERIFY_ERROR "buffer verify error: "
static inline void
buffer_verify_error (hb_buffer_t *buffer,
hb_font_t *font,
const char *fmt,
...) HB_PRINTF_FUNC(3, 4);
static inline void
buffer_verify_error (hb_buffer_t *buffer,
hb_font_t *font,
const char *fmt,
...)
{
va_list ap;
va_start (ap, fmt);
if (buffer->messaging ())
{
buffer->message_impl (font, fmt, ap);
}
else
{
fprintf (stderr, "harfbuzz ");
vfprintf (stderr, fmt, ap);
fprintf (stderr, "\n");
}
va_end (ap);
}
static bool
buffer_verify_monotone (hb_buffer_t *buffer,
hb_font_t *font)
{
/* Check that clusters are monotone. */
if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES ||
buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
{
bool is_forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
unsigned int num_glyphs;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
for (unsigned int i = 1; i < num_glyphs; i++)
if (info[i-1].cluster != info[i].cluster &&
(info[i-1].cluster < info[i].cluster) != is_forward)
{
buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "clusters are not monotone.");
return false;
}
}
return true;
}
static bool
buffer_verify_unsafe_to_break (hb_buffer_t *buffer,
hb_buffer_t *text_buffer,
hb_font_t *font,
const hb_feature_t *features,
unsigned int num_features,
const char * const *shapers)
{
if (buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES &&
buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
{
/* Cannot perform this check without monotone clusters. */
return true;
}
/* Check that breaking up shaping at safe-to-break is indeed safe. */
hb_buffer_t *fragment = hb_buffer_create_similar (buffer);
hb_buffer_set_flags (fragment, hb_buffer_get_flags (fragment) & ~HB_BUFFER_FLAG_VERIFY);
hb_buffer_t *reconstruction = hb_buffer_create_similar (buffer);
hb_buffer_set_flags (reconstruction, hb_buffer_get_flags (reconstruction) & ~HB_BUFFER_FLAG_VERIFY);
unsigned int num_glyphs;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
unsigned int num_chars;
hb_glyph_info_t *text = hb_buffer_get_glyph_infos (text_buffer, &num_chars);
/* Chop text and shape fragments. */
bool forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
unsigned int start = 0;
unsigned int text_start = forward ? 0 : num_chars;
unsigned int text_end = text_start;
for (unsigned int end = 1; end < num_glyphs + 1; end++)
{
if (end < num_glyphs &&
(info[end].cluster == info[end-1].cluster ||
info[end-(forward?0:1)].mask & HB_GLYPH_FLAG_UNSAFE_TO_BREAK))
continue;
/* Shape segment corresponding to glyphs start..end. */
if (end == num_glyphs)
{
if (forward)
text_end = num_chars;
else
text_start = 0;
}
else
{
if (forward)
{
unsigned int cluster = info[end].cluster;
while (text_end < num_chars && text[text_end].cluster < cluster)
text_end++;
}
else
{
unsigned int cluster = info[end - 1].cluster;
while (text_start && text[text_start - 1].cluster >= cluster)
text_start--;
}
}
assert (text_start < text_end);
if (0)
printf("start %d end %d text start %d end %d\n", start, end, text_start, text_end);
hb_buffer_clear_contents (fragment);
hb_buffer_flags_t flags = hb_buffer_get_flags (fragment);
if (0 < text_start)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_BOT);
if (text_end < num_chars)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_EOT);
hb_buffer_set_flags (fragment, flags);
hb_buffer_append (fragment, text_buffer, text_start, text_end);
if (!hb_shape_full (font, fragment, features, num_features, shapers))
{
buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "shaping failed while shaping fragment.");
hb_buffer_destroy (reconstruction);
hb_buffer_destroy (fragment);
return false;
}
hb_buffer_append (reconstruction, fragment, 0, -1);
start = end;
if (forward)
text_start = text_end;
else
text_end = text_start;
}
bool ret = true;
hb_buffer_diff_flags_t diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0);
if (diff)
{
buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "unsafe-to-break test failed.");
ret = false;
/* Return the reconstructed result instead so it can be inspected. */
hb_buffer_set_length (buffer, 0);
hb_buffer_append (buffer, reconstruction, 0, -1);
}
hb_buffer_destroy (reconstruction);
hb_buffer_destroy (fragment);
return ret;
}
static bool
buffer_verify_unsafe_to_concat (hb_buffer_t *buffer,
hb_buffer_t *text_buffer,
hb_font_t *font,
const hb_feature_t *features,
unsigned int num_features,
const char * const *shapers)
{
if (buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES &&
buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
{
/* Cannot perform this check without monotone clusters. */
return true;
}
/* Check that shuffling up text before shaping at safe-to-concat points
* is indeed safe. */
/* This is what we do:
*
* 1. We shape text once. Then segment the text at all the safe-to-concat
* points;
*
* 2. Then we create two buffers, one containing all the even segments and
* one all the odd segments.
*
* 3. Because all these segments were safe-to-concat at both ends, we
* expect that concatenating them and shaping should NOT change the
* shaping results of each segment. As such, we expect that after
* shaping the two buffers, we still get cluster boundaries at the
* segment boundaries, and that those all are safe-to-concat points.
* Moreover, that there are NOT any safe-to-concat points within the
* segments.
*
* 4. Finally, we reconstruct the shaping results of the original text by
* simply interleaving the shaping results of the segments from the two
* buffers, and assert that the total shaping results is the same as
* the one from original buffer in step 1.
*/
hb_buffer_t *fragments[2] {hb_buffer_create_similar (buffer),
hb_buffer_create_similar (buffer)};
hb_buffer_set_flags (fragments[0], hb_buffer_get_flags (fragments[0]) & ~HB_BUFFER_FLAG_VERIFY);
hb_buffer_set_flags (fragments[1], hb_buffer_get_flags (fragments[1]) & ~HB_BUFFER_FLAG_VERIFY);
hb_buffer_t *reconstruction = hb_buffer_create_similar (buffer);
hb_buffer_set_flags (reconstruction, hb_buffer_get_flags (reconstruction) & ~HB_BUFFER_FLAG_VERIFY);
hb_segment_properties_t props;
hb_buffer_get_segment_properties (buffer, &props);
hb_buffer_set_segment_properties (fragments[0], &props);
hb_buffer_set_segment_properties (fragments[1], &props);
hb_buffer_set_segment_properties (reconstruction, &props);
unsigned num_glyphs;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
unsigned num_chars;
hb_glyph_info_t *text = hb_buffer_get_glyph_infos (text_buffer, &num_chars);
bool forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
if (!forward)
hb_buffer_reverse (buffer);
/*
* Split text into segments and collect into to fragment streams.
*/
{
unsigned fragment_idx = 0;
unsigned start = 0;
unsigned text_start = 0;
unsigned text_end = 0;
for (unsigned end = 1; end < num_glyphs + 1; end++)
{
if (end < num_glyphs &&
(info[end].cluster == info[end-1].cluster ||
info[end].mask & HB_GLYPH_FLAG_UNSAFE_TO_CONCAT))
continue;
/* Accumulate segment corresponding to glyphs start..end. */
if (end == num_glyphs)
text_end = num_chars;
else
{
unsigned cluster = info[end].cluster;
while (text_end < num_chars && text[text_end].cluster < cluster)
text_end++;
}
assert (text_start < text_end);
if (0)
printf("start %d end %d text start %d end %d\n", start, end, text_start, text_end);
#if 0
hb_buffer_flags_t flags = hb_buffer_get_flags (fragment);
if (0 < text_start)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_BOT);
if (text_end < num_chars)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_EOT);
hb_buffer_set_flags (fragment, flags);
#endif
hb_buffer_append (fragments[fragment_idx], text_buffer, text_start, text_end);
start = end;
text_start = text_end;
fragment_idx = 1 - fragment_idx;
}
}
bool ret = true;
hb_buffer_diff_flags_t diff;
/*
* Shape the two fragment streams.
*/
if (!hb_shape_full (font, fragments[0], features, num_features, shapers))
{
buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "shaping failed while shaping fragment.");
ret = false;
goto out;
}
if (!hb_shape_full (font, fragments[1], features, num_features, shapers))
{
buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "shaping failed while shaping fragment.");
ret = false;
goto out;
}
if (!forward)
{
hb_buffer_reverse (fragments[0]);
hb_buffer_reverse (fragments[1]);
}
/*
* Reconstruct results.
*/
{
unsigned fragment_idx = 0;
unsigned fragment_start[2] {0, 0};
unsigned fragment_num_glyphs[2];
hb_glyph_info_t *fragment_info[2];
for (unsigned i = 0; i < 2; i++)
fragment_info[i] = hb_buffer_get_glyph_infos (fragments[i], &fragment_num_glyphs[i]);
while (fragment_start[0] < fragment_num_glyphs[0] ||
fragment_start[1] < fragment_num_glyphs[1])
{
unsigned fragment_end = fragment_start[fragment_idx] + 1;
while (fragment_end < fragment_num_glyphs[fragment_idx] &&
(fragment_info[fragment_idx][fragment_end].cluster == fragment_info[fragment_idx][fragment_end - 1].cluster ||
fragment_info[fragment_idx][fragment_end].mask & HB_GLYPH_FLAG_UNSAFE_TO_CONCAT))
fragment_end++;
hb_buffer_append (reconstruction, fragments[fragment_idx], fragment_start[fragment_idx], fragment_end);
fragment_start[fragment_idx] = fragment_end;
fragment_idx = 1 - fragment_idx;
}
}
if (!forward)
{
hb_buffer_reverse (buffer);
hb_buffer_reverse (reconstruction);
}
/*
* Diff results.
*/
diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0);
if (diff)
{
buffer_verify_error (buffer, font, BUFFER_VERIFY_ERROR "unsafe-to-concat test failed.");
ret = false;
/* Return the reconstructed result instead so it can be inspected. */
hb_buffer_set_length (buffer, 0);
hb_buffer_append (buffer, reconstruction, 0, -1);
}
out:
hb_buffer_destroy (reconstruction);
hb_buffer_destroy (fragments[0]);
hb_buffer_destroy (fragments[1]);
return ret;
}
bool
hb_buffer_t::verify (hb_buffer_t *text_buffer,
hb_font_t *font,
const hb_feature_t *features,
unsigned int num_features,
const char * const *shapers)
{
bool ret = true;
if (!buffer_verify_monotone (this, font))
ret = false;
if (!buffer_verify_unsafe_to_break (this, text_buffer, font, features, num_features, shapers))
ret = false;
if (!buffer_verify_unsafe_to_concat (this, text_buffer, font, features, num_features, shapers))
ret = false;
if (!ret)
{
unsigned len = text_buffer->len;
hb_vector_t<char> bytes;
if (likely (bytes.resize (len * 10 + 16)))
{
hb_buffer_serialize_unicode (text_buffer,
0, len,
bytes.arrayZ, bytes.length,
&len,
HB_BUFFER_SERIALIZE_FORMAT_TEXT,
HB_BUFFER_SERIALIZE_FLAG_NO_CLUSTERS);
buffer_verify_error (this, font, BUFFER_VERIFY_ERROR "text was: %s.", bytes.arrayZ);
}
}
return ret;
}
#endif

2
src/hb-buffer.cc
View File

@ -1789,7 +1789,7 @@ hb_buffer_add_codepoints (hb_buffer_t *buffer,
**/
HB_EXTERN void
hb_buffer_append (hb_buffer_t *buffer,
hb_buffer_t *source,
const hb_buffer_t *source,
unsigned int start,
unsigned int end)
{

51
src/hb-buffer.h
View File

@ -357,6 +357,14 @@ hb_buffer_guess_segment_properties (hb_buffer_t *buffer);
* flag indicating that a dotted circle should
* not be inserted in the rendering of incorrect
* character sequences (such at <0905 093E>). Since: 2.4
* @HB_BUFFER_FLAG_VERIFY:
* flag indicating that the hb_shape() call and its variants
* should perform various verification processes on the results
* of the shaping operation on the buffer. If the verification
* fails, then either a buffer message is sent, if a message
* handler is installed on the buffer, or a message is written
* to standard error. In either case, the shaping result might
* be modified to show the failed output.
*
* Flags for #hb_buffer_t.
*
@ -368,7 +376,8 @@ typedef enum { /*< flags >*/
HB_BUFFER_FLAG_EOT = 0x00000002u, /* End-of-text */
HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES = 0x00000004u,
HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES = 0x00000008u,
HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE = 0x00000010u
HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE = 0x00000010u,
HB_BUFFER_FLAG_VERIFY = 0x00000020u
} hb_buffer_flags_t;
HB_EXTERN void
@ -522,7 +531,7 @@ hb_buffer_add_codepoints (hb_buffer_t *buffer,
HB_EXTERN void
hb_buffer_append (hb_buffer_t *buffer,
hb_buffer_t *source,
const hb_buffer_t *source,
unsigned int start,
unsigned int end);
@ -619,24 +628,24 @@ hb_buffer_serialize_glyphs (hb_buffer_t *buffer,
HB_EXTERN unsigned int
hb_buffer_serialize_unicode (hb_buffer_t *buffer,
unsigned int start,
unsigned int end,
char *buf,
unsigned int buf_size,
unsigned int *buf_consumed,
hb_buffer_serialize_format_t format,
hb_buffer_serialize_flags_t flags);
unsigned int start,
unsigned int end,
char *buf,
unsigned int buf_size,
unsigned int *buf_consumed,
hb_buffer_serialize_format_t format,
hb_buffer_serialize_flags_t flags);
HB_EXTERN unsigned int
hb_buffer_serialize (hb_buffer_t *buffer,
unsigned int start,
unsigned int end,
char *buf,
unsigned int buf_size,
unsigned int *buf_consumed,
hb_font_t *font,
hb_buffer_serialize_format_t format,
hb_buffer_serialize_flags_t flags);
unsigned int start,
unsigned int end,
char *buf,
unsigned int buf_size,
unsigned int *buf_consumed,
hb_font_t *font,
hb_buffer_serialize_format_t format,
hb_buffer_serialize_flags_t flags);
HB_EXTERN hb_bool_t
hb_buffer_deserialize_glyphs (hb_buffer_t *buffer,
@ -648,10 +657,10 @@ hb_buffer_deserialize_glyphs (hb_buffer_t *buffer,
HB_EXTERN hb_bool_t
hb_buffer_deserialize_unicode (hb_buffer_t *buffer,
const char *buf,
int buf_len,
const char **end_ptr,
hb_buffer_serialize_format_t format);
const char *buf,
int buf_len,
const char **end_ptr,
hb_buffer_serialize_format_t format);

14
src/hb-buffer.hh
View File

@ -212,6 +212,20 @@ struct hb_buffer_t
HB_INTERNAL void enter ();
HB_INTERNAL void leave ();
#ifndef HB_NO_BUFFER_VERIFY
HB_INTERNAL
#endif
bool verify (hb_buffer_t *text_buffer,
hb_font_t *font,
const hb_feature_t *features,
unsigned int num_features,
const char * const *shapers)
#ifndef HB_NO_BUFFER_VERIFY
;
#else
{ return true; }
#endif
unsigned int backtrack_len () const { return have_output ? out_len : idx; }
unsigned int lookahead_len () const { return len - idx; }
uint8_t next_serial () { return ++serial ? serial : ++serial; }

1
src/hb-config.hh
View File

@ -55,6 +55,7 @@
#define HB_NO_ATEXIT
#define HB_NO_BUFFER_MESSAGE
#define HB_NO_BUFFER_SERIALIZE
#define HB_NO_BUFFER_VERIFY
#define HB_NO_BITMAP
#define HB_NO_CFF
#define HB_NO_COLOR

6
src/hb-ot-shape-fallback.cc
View File

@ -497,14 +497,14 @@ _hb_ot_shape_fallback_kern (const hb_ot_shape_plan_t *plan,
#endif
#ifndef HB_DISABLE_DEPRECATED
if (!buffer->message (font, "start fallback kern"))
return;
if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction) ?
!font->has_glyph_h_kerning_func () :
!font->has_glyph_v_kerning_func ())
return;
if (!buffer->message (font, "start fallback kern"))
return;
bool reverse = HB_DIRECTION_IS_BACKWARD (buffer->props.direction);
if (reverse)

18
src/hb-shape.cc
View File

@ -126,6 +126,13 @@ hb_shape_full (hb_font_t *font,
unsigned int num_features,
const char * const *shaper_list)
{
hb_buffer_t *text_buffer = nullptr;
if (buffer->flags & HB_BUFFER_FLAG_VERIFY)
{
text_buffer = hb_buffer_create ();
hb_buffer_append (text_buffer, buffer, 0, -1);
}
hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached2 (font->face, &buffer->props,
features, num_features,
font->coords, font->num_coords,
@ -133,6 +140,17 @@ hb_shape_full (hb_font_t *font,
hb_bool_t res = hb_shape_plan_execute (shape_plan, font, buffer, features, num_features);
hb_shape_plan_destroy (shape_plan);
if (text_buffer)
{
if (res && !buffer->verify (text_buffer,
font,
features,
num_features,
shaper_list))
res = false;
hb_buffer_destroy (text_buffer);
}
return res;
}

1
src/meson.build
View File

@ -29,6 +29,7 @@ hb_base_sources = files(
'hb-blob.cc',
'hb-blob.hh',
'hb-buffer-serialize.cc',
'hb-buffer-verify.cc',
'hb-buffer.cc',
'hb-buffer.hh',
'hb-cache.hh',

2
test/fuzzing/hb-shape-fuzzer.cc
View File

@ -33,6 +33,7 @@ extern "C" int LLVMFuzzerTestOneInput (const uint8_t *data, size_t size)
{
const char text[] = "ABCDEXYZ123@_%&)*$!";
hb_buffer_t *buffer = hb_buffer_create ();
// hb_buffer_set_flags (buffer, HB_BUFFER_FLAG_VERIFY);
hb_buffer_add_utf8 (buffer, text, -1, 0, -1);
hb_buffer_guess_segment_properties (buffer);
hb_shape (font, buffer, nullptr, 0);
@ -50,6 +51,7 @@ extern "C" int LLVMFuzzerTestOneInput (const uint8_t *data, size_t size)
text32[10] = test_font (font, text32[15]) % 256;
hb_buffer_t *buffer = hb_buffer_create ();
// hb_buffer_set_flags (buffer, HB_BUFFER_FLAG_VERIFY);
hb_buffer_add_utf32 (buffer, text32, sizeof (text32) / sizeof (text32[0]), 0, -1);
hb_buffer_guess_segment_properties (buffer);
hb_shape (font, buffer, nullptr, 0);

346
util/shape-options.hh
View File

@ -51,6 +51,7 @@ struct shape_options_t
(HB_BUFFER_FLAG_DEFAULT |
(bot ? HB_BUFFER_FLAG_BOT : 0) |
(eot ? HB_BUFFER_FLAG_EOT : 0) |
(verify ? HB_BUFFER_FLAG_VERIFY : 0) |
(preserve_default_ignorables ? HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES : 0) |
(remove_default_ignorables ? HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES : 0) |
0));
@ -90,365 +91,22 @@ struct shape_options_t
hb_bool_t shape (hb_font_t *font, hb_buffer_t *buffer, const char **error=nullptr)
{
hb_buffer_t *text_buffer = nullptr;
if (verify)
{
text_buffer = hb_buffer_create ();
hb_buffer_append (text_buffer, buffer, 0, -1);
}
if (!hb_shape_full (font, buffer, features, num_features, shapers))
{
if (error)
*error = "All shapers failed.";
*error = "Shaping failed.";
goto fail;
}
if (normalize_glyphs)
hb_buffer_normalize_glyphs (buffer);
if (verify && !verify_buffer (buffer, text_buffer, font, error))
goto fail;
if (text_buffer)
hb_buffer_destroy (text_buffer);
return true;
fail:
if (text_buffer)
hb_buffer_destroy (text_buffer);
return false;
}
bool verify_buffer (hb_buffer_t *buffer,
hb_buffer_t *text_buffer,
hb_font_t *font,
const char **error=nullptr)
{
if (!verify_buffer_monotone (buffer, error))
return false;
if (!verify_buffer_unsafe_to_break (buffer, text_buffer, font, error))
return false;
if (!verify_buffer_unsafe_to_concat (buffer, text_buffer, font, error))
return false;
return true;
}
bool verify_buffer_monotone (hb_buffer_t *buffer, const char **error=nullptr)
{
/* Check that clusters are monotone. */
if (cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES ||
cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
{
bool is_forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
unsigned int num_glyphs;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
for (unsigned int i = 1; i < num_glyphs; i++)
if (info[i-1].cluster != info[i].cluster &&
(info[i-1].cluster < info[i].cluster) != is_forward)
{
if (error)
*error = "clusters are not monotone.";
return false;
}
}
return true;
}
bool verify_buffer_unsafe_to_break (hb_buffer_t *buffer,
hb_buffer_t *text_buffer,
hb_font_t *font,
const char **error=nullptr)
{
if (cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES &&
cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
{
/* Cannot perform this check without monotone clusters. */
return true;
}
/* Check that breaking up shaping at safe-to-break is indeed safe. */
hb_buffer_t *fragment = hb_buffer_create_similar (buffer);
hb_buffer_t *reconstruction = hb_buffer_create_similar (buffer);
unsigned int num_glyphs;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
unsigned int num_chars;
hb_glyph_info_t *text = hb_buffer_get_glyph_infos (text_buffer, &num_chars);
/* Chop text and shape fragments. */
bool forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
unsigned int start = 0;
unsigned int text_start = forward ? 0 : num_chars;
unsigned int text_end = text_start;
for (unsigned int end = 1; end < num_glyphs + 1; end++)
{
if (end < num_glyphs &&
(info[end].cluster == info[end-1].cluster ||
info[end-(forward?0:1)].mask & HB_GLYPH_FLAG_UNSAFE_TO_BREAK))
continue;
/* Shape segment corresponding to glyphs start..end. */
if (end == num_glyphs)
{
if (forward)
text_end = num_chars;
else
text_start = 0;
}
else
{
if (forward)
{
unsigned int cluster = info[end].cluster;
while (text_end < num_chars && text[text_end].cluster < cluster)
text_end++;
}
else
{
unsigned int cluster = info[end - 1].cluster;
while (text_start && text[text_start - 1].cluster >= cluster)
text_start--;
}
}
assert (text_start < text_end);
if (0)
printf("start %d end %d text start %d end %d\n", start, end, text_start, text_end);
hb_buffer_clear_contents (fragment);
hb_buffer_flags_t flags = hb_buffer_get_flags (fragment);
if (0 < text_start)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_BOT);
if (text_end < num_chars)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_EOT);
hb_buffer_set_flags (fragment, flags);
hb_buffer_append (fragment, text_buffer, text_start, text_end);
if (!hb_shape_full (font, fragment, features, num_features, shapers))
{
if (error)
*error = "All shapers failed while shaping fragment.";
hb_buffer_destroy (reconstruction);
hb_buffer_destroy (fragment);
return false;
}
hb_buffer_append (reconstruction, fragment, 0, -1);
start = end;
if (forward)
text_start = text_end;
else
text_end = text_start;
}
bool ret = true;
hb_buffer_diff_flags_t diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0);
if (diff)
{
if (error)
*error = "unsafe-to-break test failed.";
ret = false;
/* Return the reconstructed result instead so it can be inspected. */
hb_buffer_set_length (buffer, 0);
hb_buffer_append (buffer, reconstruction, 0, -1);
}
hb_buffer_destroy (reconstruction);
hb_buffer_destroy (fragment);
return ret;
}
bool verify_buffer_unsafe_to_concat (hb_buffer_t *buffer,
hb_buffer_t *text_buffer,
hb_font_t *font,
const char **error=nullptr)
{
if (cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES &&
cluster_level != HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS)
{
/* Cannot perform this check without monotone clusters. */
return true;
}
/* Check that shuffling up text before shaping at safe-to-concat points
* is indeed safe. */
/* This is what we do:
*
* 1. We shape text once. Then segment the text at all the safe-to-concat
* points;
*
* 2. Then we create two buffers, one containing all the even segments and
* one all the odd segments.
*
* 3. Because all these segments were safe-to-concat at both ends, we
* expect that concatenating them and shaping should NOT change the
* shaping results of each segment. As such, we expect that after
* shaping the two buffers, we still get cluster boundaries at the
* segment boundaries, and that those all are safe-to-concat points.
* Moreover, that there are NOT any safe-to-concat points within the
* segments.
*
* 4. Finally, we reconstruct the shaping results of the original text by
* simply interleaving the shaping results of the segments from the two
* buffers, and assert that the total shaping results is the same as
* the one from original buffer in step 1.
*/
hb_buffer_t *fragments[2] {hb_buffer_create_similar (buffer),
hb_buffer_create_similar (buffer)};
hb_buffer_t *reconstruction = hb_buffer_create_similar (buffer);
hb_segment_properties_t props;
hb_buffer_get_segment_properties (buffer, &props);
hb_buffer_set_segment_properties (fragments[0], &props);
hb_buffer_set_segment_properties (fragments[1], &props);
hb_buffer_set_segment_properties (reconstruction, &props);
unsigned num_glyphs;
hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, &num_glyphs);
unsigned num_chars;
hb_glyph_info_t *text = hb_buffer_get_glyph_infos (text_buffer, &num_chars);
bool forward = HB_DIRECTION_IS_FORWARD (hb_buffer_get_direction (buffer));
if (!forward)
hb_buffer_reverse (buffer);
/*
* Split text into segments and collect into to fragment streams.
*/
{
unsigned fragment_idx = 0;
unsigned start = 0;
unsigned text_start = 0;
unsigned text_end = 0;
for (unsigned end = 1; end < num_glyphs + 1; end++)
{
if (end < num_glyphs &&
(info[end].cluster == info[end-1].cluster ||
info[end].mask & HB_GLYPH_FLAG_UNSAFE_TO_CONCAT))
continue;
/* Accumulate segment corresponding to glyphs start..end. */
if (end == num_glyphs)
text_end = num_chars;
else
{
unsigned cluster = info[end].cluster;
while (text_end < num_chars && text[text_end].cluster < cluster)
text_end++;
}
assert (text_start < text_end);
if (0)
printf("start %d end %d text start %d end %d\n", start, end, text_start, text_end);
#if 0
hb_buffer_flags_t flags = hb_buffer_get_flags (fragment);
if (0 < text_start)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_BOT);
if (text_end < num_chars)
flags = (hb_buffer_flags_t) (flags & ~HB_BUFFER_FLAG_EOT);
hb_buffer_set_flags (fragment, flags);
#endif
hb_buffer_append (fragments[fragment_idx], text_buffer, text_start, text_end);
start = end;
text_start = text_end;
fragment_idx = 1 - fragment_idx;
}
}
bool ret = true;
hb_buffer_diff_flags_t diff;
/*
* Shape the two fragment streams.
*/
if (!hb_shape_full (font, fragments[0], features, num_features, shapers) ||
!hb_shape_full (font, fragments[1], features, num_features, shapers))
{
if (error)
*error = "All shapers failed while shaping fragments.";
ret = false;
goto out;
}
if (!forward)
{
hb_buffer_reverse (fragments[0]);
hb_buffer_reverse (fragments[1]);
}
/*
* Reconstruct results.
*/
{
unsigned fragment_idx = 0;
unsigned fragment_start[2] {0, 0};
unsigned fragment_num_glyphs[2];
hb_glyph_info_t *fragment_info[2];
for (unsigned i = 0; i < 2; i++)
fragment_info[i] = hb_buffer_get_glyph_infos (fragments[i], &fragment_num_glyphs[i]);
while (fragment_start[0] < fragment_num_glyphs[0] ||
fragment_start[1] < fragment_num_glyphs[1])
{
unsigned fragment_end = fragment_start[fragment_idx] + 1;
while (fragment_end < fragment_num_glyphs[fragment_idx] &&
(fragment_info[fragment_idx][fragment_end].cluster == fragment_info[fragment_idx][fragment_end - 1].cluster ||
fragment_info[fragment_idx][fragment_end].mask & HB_GLYPH_FLAG_UNSAFE_TO_CONCAT))
fragment_end++;
hb_buffer_append (reconstruction, fragments[fragment_idx], fragment_start[fragment_idx], fragment_end);
fragment_start[fragment_idx] = fragment_end;
fragment_idx = 1 - fragment_idx;
}
}
if (!forward)
{
hb_buffer_reverse (buffer);
hb_buffer_reverse (reconstruction);
}
/*
* Diff results.
*/
diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0);
if (diff)
{
if (error)
*error = "unsafe-to-concat test failed.";
ret = false;
/* Return the reconstructed result instead so it can be inspected. */
hb_buffer_set_length (buffer, 0);
hb_buffer_append (buffer, reconstruction, 0, -1);
}
out:
hb_buffer_destroy (reconstruction);
hb_buffer_destroy (fragments[0]);
hb_buffer_destroy (fragments[1]);
return ret;
}
void shape_closure (const char *text, int text_len,
hb_font_t *font, hb_buffer_t *buffer,
hb_set_t *glyphs)