diff options
Diffstat (limited to 'gfx/harfbuzz/src/hb-buffer-verify.cc')
| -rw-r--r-- | gfx/harfbuzz/src/hb-buffer-verify.cc | 423 |
1 files changed, 423 insertions, 0 deletions
diff --git a/gfx/harfbuzz/src/hb-buffer-verify.cc b/gfx/harfbuzz/src/hb-buffer-verify.cc new file mode 100644 index 0000000000..15a53919de --- /dev/null +++ b/gfx/harfbuzz/src/hb-buffer-verify.cc @@ -0,0 +1,423 @@ +/* + * 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_flags_t (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_flags_t (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 %u end %u text start %u end %u\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) || + fragment->successful || fragment->shaping_failed) + { + hb_buffer_destroy (reconstruction); + hb_buffer_destroy (fragment); + return true; + } + hb_buffer_append (reconstruction, fragment, 0, -1); + + start = end; + if (forward) + text_start = text_end; + else + text_end = text_start; + } + + bool ret = true; + if (likely (reconstruction->successful)) + { + hb_buffer_diff_flags_t diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0); + if (diff & ~HB_BUFFER_DIFF_FLAG_GLYPH_FLAGS_MISMATCH) + { + 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_flags_t (hb_buffer_get_flags (fragments[0]) & ~HB_BUFFER_FLAG_VERIFY))); + hb_buffer_set_flags (fragments[1], (hb_buffer_flags_t (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_flags_t (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 %u end %u text start %u end %u\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) || + !fragments[0]->successful || fragments[0]->shaping_failed) + goto out; + + if (!hb_shape_full (font, fragments[1], features, num_features, shapers) || + !fragments[1]->successful || fragments[1]->shaping_failed) + 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); + } + + if (likely (reconstruction->successful)) + { + /* + * Diff results. + */ + diff = hb_buffer_diff (reconstruction, buffer, (hb_codepoint_t) -1, 0); + if (diff & ~HB_BUFFER_DIFF_FLAG_GLYPH_FLAGS_MISMATCH) + { + 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 ((flags & HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT) != 0 && + !buffer_verify_unsafe_to_concat (this, text_buffer, font, features, num_features, shapers)) + ret = false; + if (!ret) + { +#ifndef HB_NO_BUFFER_SERIALIZE + 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); + } +#endif + } + return ret; +} + + +#endif |