SkPDF: SkTypeface::openStream could return nullptr

src/pdf/SkPDFFont.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include <ctype.h>
 
 #include "SkData.h"
@@ skipping 572 matching lines @@
 }
 #endif
 
 #if defined(SK_SFNTLY_SUBSETTER)
 static size_t get_subset_font_stream(const char* fontName,
                                      const SkTypeface* typeface,
                                      const SkTDArray<uint32_t>& subset,
                                      SkPDFStream** fontStream) {
     int ttcIndex;
     std::unique_ptr<SkStream> fontData(typeface->openStream(&ttcIndex));
-    SkASSERT(fontData.get());
+    SkASSERT(fontData);
+    if (!fontData) {
+        return 0;
+    }
 
     size_t fontSize = fontData->getLength();
 
     // Read font into buffer.
     SkPDFStream* subsetFontStream = nullptr;
     SkTDArray<unsigned char> originalFont;
     originalFont.setCount(SkToInt(fontSize));
     if (fontData->read(originalFont.begin(), fontSize) == fontSize) {
         unsigned char* subsetFont = nullptr;
         // sfntly requires unsigned int* to be passed in, as far as we know,
@@ skipping 436 matching lines @@
         case SkAdvancedTypefaceMetrics::kTrueType_Font: {
             size_t fontSize = 0;
 #if defined(SK_SFNTLY_SUBSETTER)
             if (this->canSubset()) {
                 sk_sp<SkPDFStream> fontStream;
                 SkPDFStream* rawStream = nullptr;
                 fontSize = get_subset_font_stream(fontInfo()->fFontName.c_str(),
                                                   typeface(),
                                                   *subset,
                                                   &rawStream);
+                if (0 == fontSize) {
+                    return false;
+                }
                 if (rawStream) {
                     fontStream.reset(rawStream);
                     fontStream->insertInt("Length1", fontSize);
                     descriptor->insertObjRef("FontFile2", std::move(fontStream));
                     break;
                 }
             }
 #endif
             sk_sp<SkPDFSharedStream> fontStream;
             std::unique_ptr<SkStreamAsset> fontData(
                     this->typeface()->openStream(nullptr));
             SkASSERT(fontData);
+            if (!fontData || 0 == fontData->getLength()) {
+                return false;
+            }
             fontSize = fontData->getLength();
             SkASSERT(fontSize > 0);
             fontStream.reset(new SkPDFSharedStream(fontData.release()));
             fontStream->dict()->insertInt("Length1", fontSize);
             descriptor->insertObjRef("FontFile2", std::move(fontStream));
             break;
         }
         case SkAdvancedTypefaceMetrics::kCFF_Font:
         case SkAdvancedTypefaceMetrics::kType1CID_Font: {
+            std::unique_ptr<SkStreamAsset> fontData(
+                    this->typeface()->openStream(nullptr));
+            SkASSERT(fontData);
+            SkASSERT(fontData->getLength() > 0);
+            if (!fontData || 0 == fontData->getLength()) {
+                return false;
+            }
             sk_sp<SkPDFSharedStream> fontStream(
-                    new SkPDFSharedStream(this->typeface()->openStream(nullptr)));
-
+                    new SkPDFSharedStream(fontData.release()));
             if (getType() == SkAdvancedTypefaceMetrics::kCFF_Font) {
                 fontStream->dict()->insertName("Subtype", "Type1C");
             } else {
                 fontStream->dict()->insertName("Subtype", "CIDFontType0c");
             }
             descriptor->insertObjRef("FontFile3", std::move(fontStream));
             break;
         }
         default:
             SkASSERT(false);
@@ skipping 107 matching lines @@
         return true;
     }
 
     auto descriptor = sk_make_sp<SkPDFDict>("FontDescriptor");
     setFontDescriptor(descriptor.get());
 
     int ttcIndex;
     size_t header SK_INIT_TO_AVOID_WARNING;
     size_t data SK_INIT_TO_AVOID_WARNING;
     size_t trailer SK_INIT_TO_AVOID_WARNING;
-    std::unique_ptr<SkStream> rawFontData(typeface()->openStream(&ttcIndex));
+    std::unique_ptr<SkStreamAsset> rawFontData(typeface()->openStream(&ttcIndex));
+    SkASSERT(rawFontData);
+    SkASSERT(rawFontData->getLength() > 0);
+    if (!rawFontData || 0 == rawFontData->getLength()) {
+        return false;
+    }
     sk_sp<SkData> fontData(handle_type1_stream(rawFontData.get(), &header,
                                                       &data, &trailer));
     if (fontData.get() == nullptr) {
         return false;
     }
     SkASSERT(this->canEmbed());
     auto fontStream = sk_make_sp<SkPDFStream>(fontData.get());
     fontStream->insertInt("Length1", header);
     fontStream->insertInt("Length2", data);
     fontStream->insertInt("Length3", trailer);
@@ skipping 206 matching lines @@
     }
     return *canon->fCanEmbedTypeface.set(id, canEmbed);
 }
 
 void SkPDFFont::drop() {
     fTypeface = nullptr;
     fFontInfo = nullptr;
     fDescriptor = nullptr;
     this->SkPDFDict::drop();
 }