Reland: Small fix in CPDF_TrueTypeFont load

The ToUnicode map should not be ignored when it exists. Doing so can cause a
charcode to be assigned an incorrect glyph index, and will result in garbled
text.

Previously, some bots failed with 'unable to open' the .png file.

Bug: chromium:665467
Change-Id: I435a73647eadcc3ba37bb0120f3b5cee381ae7a3
Reviewed-on: https://pdfium-review.googlesource.com/5610
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Nicolás Peña <npm@chromium.org>

4 files changed, 117 insertions, 22 deletions

diff --git a/core/fpdfapi/font/cpdf_truetypefont.cpp b/core/fpdfapi/font/cpdf_truetypefont.cpp
index d78a5e0eb2..7f4512da05 100644
--- a/core/fpdfapi/font/cpdf_truetypefont.cpp
+++ b/core/fpdfapi/font/cpdf_truetypefont.cpp
@@ -125,28 +125,24 @@ void CPDF_TrueTypeFont::LoadGlyphMap() {
           }
         }
       }
-      if ((m_GlyphIndex[charcode] == 0 || m_GlyphIndex[charcode] == 0xffff) &&
-          name) {
-        if (name[0] == '.' && strcmp(name, ".notdef") == 0) {
-          m_GlyphIndex[charcode] = FXFT_Get_Char_Index(m_Font.GetFace(), 32);
-        } else {
-          m_GlyphIndex[charcode] =
-              FXFT_Get_Name_Index(m_Font.GetFace(), (char*)name);
-          if (m_GlyphIndex[charcode] == 0) {
-            if (bToUnicode) {
-              CFX_WideString wsUnicode = UnicodeFromCharCode(charcode);
-              if (!wsUnicode.IsEmpty()) {
-                m_GlyphIndex[charcode] =
-                    FXFT_Get_Char_Index(m_Font.GetFace(), wsUnicode[0]);
-                m_Encoding.m_Unicodes[charcode] = wsUnicode[0];
-              }
-            }
-            if (m_GlyphIndex[charcode] == 0) {
-              m_GlyphIndex[charcode] =
-                  FXFT_Get_Char_Index(m_Font.GetFace(), charcode);
-            }
-          }
-        }
+      if ((m_GlyphIndex[charcode] != 0 && m_GlyphIndex[charcode] != 0xffff) ||
+          !name) {
+        continue;
+      }
+      if (strcmp(name, ".notdef") == 0) {
+        m_GlyphIndex[charcode] = FXFT_Get_Char_Index(m_Font.GetFace(), 32);
+        continue;
+      }
+      m_GlyphIndex[charcode] =
+          FXFT_Get_Name_Index(m_Font.GetFace(), (char*)name);
+      if (m_GlyphIndex[charcode] != 0 || !bToUnicode)
+        continue;
+
+      CFX_WideString wsUnicode = UnicodeFromCharCode(charcode);
+      if (!wsUnicode.IsEmpty()) {
+        m_GlyphIndex[charcode] =
+            FXFT_Get_Char_Index(m_Font.GetFace(), wsUnicode[0]);
+        m_Encoding.m_Unicodes[charcode] = wsUnicode[0];
       }
     }
     return;
diff --git a/testing/resources/pixel/bug_665467.in b/testing/resources/pixel/bug_665467.in
new file mode 100644
index 0000000000..6ef2c1cb82
--- /dev/null
+++ b/testing/resources/pixel/bug_665467.in
@@ -0,0 +1,99 @@
+{{header}}
+{{object 1 0}} <<
+  /Type /Catalog
+  /Pages 2 0 R
+>>
+endobj
+
+{{object 2 0}} <<
+  /Type /Pages
+  /MediaBox [ 0 0 100 100 ]
+  /Count 1
+  /Kids [ 3 0 R ]
+>>
+endobj
+
+{{object 3 0}} <<
+  /Type /Page
+  /Parent 2 0 R
+  /Resources
+  <<
+    /Font << /F1 4 0 R >>
+  >>
+  /Contents 8 0 R
+>>
+endobj
+
+{{object 4 0}} <<
+  /Type /Font
+  /Subtype /TrueType
+  /BaseFont /ChromeSansMM
+  /Encoding 5 0 R
+  /FirstChar 32
+  /LastChar 255
+  /Name /F1
+  /ToUnicode 6 0 R
+  /FontDescriptor 7 0 R
+>>
+endobj
+
+{{object 5 0}} <<
+  /Differences [ 161 /someunknownname ]
+  /Type /Encoding
+>>
+endobj
+
+{{object 6 0}} <<
+>>
+stream
+/CIDInit /ProcSet findresource begin
+12 dict begin
+begincmap
+/CIDSystemInfo
+<</Registry (Adobe)
+/Ordering (Identity)
+/Supplement 0
+>> def
+/CMapName /Adobe-Identity-H def
+CMapType 2 def
+1 begincodespacerange
+<00> <FF>
+endcodespacerange
+1 beginbfchar
+<A1> <043B>
+endbfchar
+endcmap
+CMapName currentdict /CMap defineresource pop
+end
+end
+endstream
+endobj
+
+{{object 7 0}} <<
+  << /Ascent 1000
+  /CapHeight 0
+  /Descent -200
+  /Flags 32
+  /FontBBox [ -599 -207 1338 1034 ]
+  /FontName /ChromeSansMM
+  /ItalicAngle 0
+  /StemV 0
+  /Type /FontDescriptor
+>>
+endobj
+
+{{object 8 0}} <<
+>>
+stream
+BT
+50 50 Td /F1 15 Tf <A1> Tj
+ET
+endstream
+endobj
+
+{{xref}}
+trailer <<
+  /Root 1 0 R
+>>
+{{startxref}}
+%%EOF
diff --git a/testing/resources/pixel/bug_665467_expected.pdf.0.png b/testing/resources/pixel/bug_665467_expected.pdf.0.png
new file mode 100644
index 0000000000..617cb0a916
--- /dev/null
+++ b/testing/resources/pixel/bug_665467_expected.pdf.0.png
diff --git a/testing/resources/pixel/bug_665467_expected_mac.pdf.0.png b/testing/resources/pixel/bug_665467_expected_mac.pdf.0.png
new file mode 100644
index 0000000000..9f51dcb855
--- /dev/null
+++ b/testing/resources/pixel/bug_665467_expected_mac.pdf.0.png