Nikolay Sivov : dwrite/layout: Limit text window passed to MapCharacters() to the range of characters to map.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 47b2750309010092eb840b83d22c10a5e84d56f6
URL:    https://gitlab.winehq.org/wine/wine/-/commit/47b2750309010092eb840b83d22c10a...

Author: Nikolay Sivov 
Date:   Tue Sep 13 10:50:05 2022 +0300

dwrite/layout: Limit text window passed to MapCharacters() to the range of characters to map.

Fallback instance does not get access to layout contents outside of given range. This could
be observed with a custom fallback.

Signed-off-by: Nikolay Sivov

---

dlls/dwrite/layout.c | 61 +++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 44 insertions(+), 17 deletions(-)

diff --git a/dlls/dwrite/layout.c b/dlls/dwrite/layout.c
index 6dca45bf376..0d08ba99de6 100644
--- a/dlls/dwrite/layout.c
+++ b/dlls/dwrite/layout.c
@@ -1,5 +1,5 @@
 /*
- * Copyright 2012, 2014-2021 Nikolay Sivov for CodeWeavers
+ * Copyright 2012, 2014-2022 Nikolay Sivov for CodeWeavers
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -226,6 +226,13 @@ struct dwrite_textlayout

WCHAR *str;
     UINT32 len;
+
+    struct
+    {
+        unsigned int offset;
+        unsigned int length;
+    } text_source;
+
     struct dwrite_textformat_data format;
     struct list strike_ranges;
     struct list underline_ranges;
@@ -595,6 +602,13 @@ static inline void layout_get_font_height(float emsize, const DWRITE_FONT_METRIC
     *height = SCALE_FONT_METRIC(fontmetrics->ascent + fontmetrics->descent + fontmetrics->lineGap, emsize, fontmetrics);
 }

+static inline void layout_initialize_text_source(struct dwrite_textlayout *layout, unsigned int offset,
+        unsigned int length)
+{
+    layout->text_source.offset = offset;
+    layout->text_source.length = length;
+}
+
 static HRESULT layout_itemize(struct dwrite_textlayout *layout)
 {
     IDWriteTextAnalyzer2 *analyzer;
@@ -604,6 +618,7 @@ static HRESULT layout_itemize(struct dwrite_textlayout *layout)

analyzer = get_text_analyzer();

+    layout_initialize_text_source(layout, 0, layout->len);
     LIST_FOR_EACH_ENTRY(range, &layout->ranges, struct layout_range, h.entry) {
         /* We don't care about ranges that don't contain any text. */
         if (range->h.range.startPosition >= layout->len)
@@ -666,9 +681,10 @@ static HRESULT layout_map_run_characters(struct dwrite_textlayout *layout, struc

run = &r->u.regular;

+        layout_initialize_text_source(layout, run->descr.textPosition, run->descr.stringLength);
         hr = IDWriteFontFallback_MapCharacters(fallback, (IDWriteTextAnalysisSource *)&layout->IDWriteTextAnalysisSource1_iface,
-                run->descr.textPosition, run->descr.stringLength, collection, range->fontfamily, range->weight,
-                range->style, range->stretch, &mapped_length, &font, &scale);
+                0, run->descr.stringLength, collection, range->fontfamily, range->weight, range->style, range->stretch,
+                &mapped_length, &font, &scale);
         if (FAILED(hr))
         {
             WARN("%s: failed to map family %s, collection %p, hr %#lx.\n", debugstr_rundescr(&run->descr),
@@ -1238,6 +1254,7 @@ static HRESULT layout_compute(struct dwrite_textlayout *layout)

analyzer = get_text_analyzer();

+        layout_initialize_text_source(layout, 0, layout->len);
         if (FAILED(hr = IDWriteTextAnalyzer2_AnalyzeLineBreakpoints(analyzer,
                 (IDWriteTextAnalysisSource *)&layout->IDWriteTextAnalysisSource1_iface,
                 0, layout->len, (IDWriteTextAnalysisSink *)&layout->IDWriteTextAnalysisSink1_iface)))
@@ -5047,11 +5064,13 @@ static HRESULT WINAPI dwritetextlayout_source_GetTextAtPosition(IDWriteTextAnaly

TRACE("%p, %u, %p, %p.\n", iface, position, text, text_len);

-    if (position < layout->len) {
-        *text = &layout->str[position];
-        *text_len = layout->len - position;
+    if (position < layout->text_source.length)
+    {
+        *text = &layout->str[position + layout->text_source.offset];
+        *text_len = layout->text_source.length - position;
     }
-    else {
+    else
+    {
         *text = NULL;
         *text_len = 0;
     }
@@ -5066,11 +5085,13 @@ static HRESULT WINAPI dwritetextlayout_source_GetTextBeforePosition(IDWriteTextA

TRACE("%p, %u, %p, %p.\n", iface, position, text, text_len);

-    if (position > 0 && position < layout->len) {
-        *text = layout->str;
+    if (position && position < layout->text_source.length)
+    {
+        *text = &layout->str[layout->text_source.offset];
         *text_len = position;
     }
-    else {
+    else
+    {
         *text = NULL;
         *text_len = 0;
     }
@@ -5088,24 +5109,30 @@ static HRESULT WINAPI dwritetextlayout_source_GetLocaleName(IDWriteTextAnalysisS
     UINT32 position, UINT32* text_len, WCHAR const** locale)
 {
     struct dwrite_textlayout *layout = impl_from_IDWriteTextAnalysisSource1(iface);
-    struct layout_range *range = get_layout_range_by_pos(layout, position);
+    struct layout_range *range, *next;
+    unsigned int end;

-    if (position < layout->len) {
-        struct layout_range *next;
+    if (position < layout->text_source.length)
+    {
+        position += layout->text_source.offset;
+        end = layout->text_source.offset + layout->text_source.length;
+
+        range = get_layout_range_by_pos(layout, position);

*locale = range->locale;
-        *text_len = range->h.range.length - position;
+        *text_len = range->h.range.startPosition + range->h.range.length - position;

next = LIST_ENTRY(list_next(&layout->ranges, &range->h.entry), struct layout_range, h.entry);
-        while (next && next->h.range.startPosition < layout->len && !wcscmp(range->locale, next->locale))
+        while (next && next->h.range.startPosition < end && !wcscmp(range->locale, next->locale))
         {
             *text_len += next->h.range.length;
             next = LIST_ENTRY(list_next(&layout->ranges, &next->h.entry), struct layout_range, h.entry);
         }

-        *text_len = min(*text_len, layout->len - position);
+        *text_len = min(*text_len, layout->text_source.length - position);
     }
-    else {
+    else
+    {
         *locale = NULL;
         *text_len = 0;
     }