Fixed issue found by clusterfuzz

tests/SerializationTest.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapDevice.h"
 #include "SkBitmapSource.h"
 #include "SkCanvas.h"
@@ skipping 48 matching lines @@
 
 template<> struct SerializationUtils<SkRegion> {
     static void Write(SkWriteBuffer& writer, const SkRegion* region) {
         writer.writeRegion(*region);
     }
     static void Read(SkValidatingReadBuffer& reader, SkRegion* region) {
         reader.readRegion(region);
     }
 };
 
+template<> struct SerializationUtils<SkString> {
+    static void Write(SkWriteBuffer& writer, const SkString* string) {
+        writer.writeString(string->c_str());
+    }
+    static void Read(SkValidatingReadBuffer& reader, SkString* string) {
+        reader.readString(string);
+    }
+};
+
 template<> struct SerializationUtils<unsigned char> {
     static void Write(SkWriteBuffer& writer, unsigned char* data, uint32_t arraySize) {
         writer.writeByteArray(data, arraySize);
     }
     static bool Read(SkValidatingReadBuffer& reader, unsigned char* data, uint32_t arraySize) {
         return reader.readByteArray(data, arraySize);
     }
 };
 
 template<> struct SerializationUtils<SkColor> {
@@ skipping 25 matching lines @@
 
 template<> struct SerializationUtils<SkScalar> {
     static void Write(SkWriteBuffer& writer, SkScalar* data, uint32_t arraySize) {
         writer.writeScalarArray(data, arraySize);
     }
     static bool Read(SkValidatingReadBuffer& reader, SkScalar* data, uint32_t arraySize) {
         return reader.readScalarArray(data, arraySize);
     }
 };
 
-template<typename T>
-static void TestObjectSerialization(T* testObj, skiatest::Reporter* reporter) {
+template<typename T, bool testInvalid> struct SerializationTestUtils {
+    static void InvalidateData(unsigned char* data) {}
+};
+
+template<> struct SerializationTestUtils<SkString, true> {
+    static void InvalidateData(unsigned char* data) {
+        data[3] |= 0x80; // Reverse sign of 1st integer
+    }
+};
+
+template<typename T, bool testInvalid>
+static void TestObjectSerializationNoAlign(T* testObj, skiatest::Reporter* reporter) {
     SkWriteBuffer writer(SkWriteBuffer::kValidation_Flag);
     SerializationUtils<T>::Write(writer, testObj);
     size_t bytesWritten = writer.bytesWritten();
     REPORTER_ASSERT(reporter, SkAlign4(bytesWritten) == bytesWritten);
 
     unsigned char dataWritten[1024];
     writer.writeToMemory(dataWritten);
 
+    SerializationTestUtils<T, testInvalid>::InvalidateData(dataWritten);
+
     // Make sure this fails when it should (test with smaller size, but still multiple of 4)
     SkValidatingReadBuffer buffer(dataWritten, bytesWritten - 4);
     T obj;
     SerializationUtils<T>::Read(buffer, &obj);
     REPORTER_ASSERT(reporter, !buffer.isValid());
 
     // Make sure this succeeds when it should
     SkValidatingReadBuffer buffer2(dataWritten, bytesWritten);
     const unsigned char* peekBefore = static_cast<const unsigned char*>(buffer2.skip(0));
     T obj2;
     SerializationUtils<T>::Read(buffer2, &obj2);
     const unsigned char* peekAfter = static_cast<const unsigned char*>(buffer2.skip(0));
     // This should have succeeded, since there are enough bytes to read this
-    REPORTER_ASSERT(reporter, buffer2.isValid());
+    REPORTER_ASSERT(reporter, buffer2.isValid() == !testInvalid);
+    // Note: This following test should always succeed, regardless of whether the buffer is valid,
+    // since if it is invalid, it will simply skip to the end, as if it had read the whole buffer.
     REPORTER_ASSERT(reporter, static_cast<size_t>(peekAfter - peekBefore) == bytesWritten);
+}
 
+template<typename T>
+static void TestObjectSerialization(T* testObj, skiatest::Reporter* reporter) {
+    TestObjectSerializationNoAlign<T, false>(testObj, reporter);
     TestAlignment(testObj, reporter);
 }
 
 template<typename T>
 static T* TestFlattenableSerialization(T* testObj, bool shouldSucceed,
                                        skiatest::Reporter* reporter) {
     SkWriteBuffer writer(SkWriteBuffer::kValidation_Flag);
     SerializationUtils<T>::Write(writer, testObj);
     size_t bytesWritten = writer.bytesWritten();
     REPORTER_ASSERT(reporter, SkAlign4(bytesWritten) == bytesWritten);
@@ skipping 152 matching lines @@
         SkPath path;
         TestObjectSerialization(&path, reporter);
     }
 
     // Test region serialization
     {
         SkRegion region;
         TestObjectSerialization(&region, reporter);
     }
 
+    // Test string serialization
+    {
+        SkString string("string");
+        TestObjectSerializationNoAlign<SkString, false>(&string, reporter);
+        TestObjectSerializationNoAlign<SkString, true>(&string, reporter);
+    }
+
     // Test rrect serialization
     {
         // SkRRect does not initialize anything.
         // An uninitialized SkRRect can be serialized,
         // but will branch on uninitialized data when deserialized.
         SkRRect rrect;
         SkRect rect = SkRect::MakeXYWH(1, 2, 20, 30);
         SkVector corners[4] = { {1, 2}, {2, 3}, {3,4}, {4,5} };
         rrect.setRectRadii(rect, corners);
         TestAlignment(&rrect, reporter);
@@ skipping 60 matching lines @@
         SkAutoTMalloc<unsigned char> data(size);
         writer.writeToMemory(static_cast<void*>(data.get()));
 
         // Deserialize picture
         SkValidatingReadBuffer reader(static_cast<void*>(data.get()), size);
         SkAutoTUnref<SkPicture> readPict(
             SkPicture::CreateFromBuffer(reader));
         REPORTER_ASSERT(reporter, NULL != readPict.get());
     }
 }