Initial error handling code

src/core/SkSecureReadBuffer.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 "SkBitmap.h"
+#include "SkErrorInternals.h"
+#include "SkSecureReadBuffer.h"
+#include "SkStream.h"
+#include "SkTypeface.h"
+
+SkSecureReadBuffer::SkSecureReadBuffer() : INHERITED() {
+    fMemoryPtr = NULL;
+
+    fBitmapStorage = NULL;
+    fTFArray = NULL;
+    fTFCount = 0;
+
+    fFactoryTDArray = NULL;
+    fFactoryArray = NULL;
+    fFactoryCount = 0;
+    fBitmapDecoder = NULL;
+#ifdef DEBUG_NON_DETERMINISTIC_ASSERT
+    fDecodedBitmapIndex = -1;
+#endif // DEBUG_NON_DETERMINISTIC_ASSERT
+
+    setFlags(SkFlattenableReadBuffer::kSecure_Flag);
+}
+
+SkSecureReadBuffer::SkSecureReadBuffer(const void* data, size_t size) : INHERITED()  {
+    fReader.setMemory(data, size);
+    fMemoryPtr = NULL;
+
+    fBitmapStorage = NULL;
+    fTFArray = NULL;
+    fTFCount = 0;
+
+    fFactoryTDArray = NULL;
+    fFactoryArray = NULL;
+    fFactoryCount = 0;
+    fBitmapDecoder = NULL;
+#ifdef DEBUG_NON_DETERMINISTIC_ASSERT
+    fDecodedBitmapIndex = -1;
+#endif // DEBUG_NON_DETERMINISTIC_ASSERT
+
+    setFlags(SkFlattenableReadBuffer::kSecure_Flag);
+}
+
+SkSecureReadBuffer::SkSecureReadBuffer(SkStream* stream) {
+    const size_t length = stream->getLength();
+    fMemoryPtr = sk_malloc_throw(length);
+    stream->read(fMemoryPtr, length);
+    fReader.setMemory(fMemoryPtr, length);
+
+    fBitmapStorage = NULL;
+    fTFArray = NULL;
+    fTFCount = 0;
+
+    fFactoryTDArray = NULL;
+    fFactoryArray = NULL;
+    fFactoryCount = 0;
+    fBitmapDecoder = NULL;
+#ifdef DEBUG_NON_DETERMINISTIC_ASSERT
+    fDecodedBitmapIndex = -1;
+#endif // DEBUG_NON_DETERMINISTIC_ASSERT
+
+    setFlags(SkFlattenableReadBuffer::kSecure_Flag);
+}
+
+SkSecureReadBuffer::~SkSecureReadBuffer() {
+    sk_free(fMemoryPtr);
+    SkSafeUnref(fBitmapStorage);
+}
+
+bool SkSecureReadBuffer::readBool() {
+    return fReader.readBool();
+}
+
+SkColor SkSecureReadBuffer::readColor() {
+    return fReader.readInt();
+}
+
+SkFixed SkSecureReadBuffer::readFixed() {
+    return fReader.readS32();
+}
+
+int32_t SkSecureReadBuffer::readInt() {
+    return fReader.readInt();
+}
+
+SkScalar SkSecureReadBuffer::readScalar() {
+    return fReader.readScalar();
+}
+
+uint32_t SkSecureReadBuffer::readUInt() {
+    return fReader.readU32();
+}
+
+int32_t SkSecureReadBuffer::read32() {
+    return fReader.readInt();
+}
+
+void SkSecureReadBuffer::readString(SkString* string) {
+    size_t len;
+    const char* strContents = fReader.readString(&len);
+    string->set(strContents, len);
+}
+
+void* SkSecureReadBuffer::readEncodedString(size_t* length, SkPaint::TextEncoding encoding) {
+    int32_t encodingType = fReader.readInt();
+    if (encodingType == encoding) {
+        fReader.setError();
+    }
+    *length = fReader.readInt();
+    const void* ptr = fReader.skip(SkAlign4(*length));
+    void* data = NULL;
+    if (!fReader.getError()) {
+        data = sk_malloc_throw(*length);
+        memcpy(data, ptr, *length);
+    }
+    return data;
+}
+
+void SkSecureReadBuffer::readPoint(SkPoint* point) {
+    point->fX = fReader.readScalar();
+    point->fY = fReader.readScalar();
+}
+
+void SkSecureReadBuffer::readMatrix(SkMatrix* matrix) {
+    fReader.readMatrix(matrix);
+}
+
+void SkSecureReadBuffer::readIRect(SkIRect* rect) {
+    memcpy(rect, fReader.skip(sizeof(SkIRect)), sizeof(SkIRect));
+}
+
+void SkSecureReadBuffer::readRect(SkRect* rect) {
+    memcpy(rect, fReader.skip(sizeof(SkRect)), sizeof(SkRect));
+}
+
+void SkSecureReadBuffer::readRegion(SkRegion* region) {
+    fReader.readRegion(region);
+}
+
+void SkSecureReadBuffer::readPath(SkPath* path) {
+    fReader.readPath(path);
+}
+
+uint32_t SkSecureReadBuffer::readByteArray(void* value) {
+    const uint32_t length = fReader.readU32();
+    memcpy(value, fReader.skip(SkAlign4(length)), length);
+    return length;
+}
+
+uint32_t SkSecureReadBuffer::readColorArray(SkColor* colors) {
+    const uint32_t count = fReader.readU32();
+    const uint32_t byteLength = count * sizeof(SkColor);
+    memcpy(colors, fReader.skip(SkAlign4(byteLength)), byteLength);
+    return count;
+}
+
+uint32_t SkSecureReadBuffer::readIntArray(int32_t* values) {
+    const uint32_t count = fReader.readU32();
+    const uint32_t byteLength = count * sizeof(int32_t);
+    memcpy(values, fReader.skip(SkAlign4(byteLength)), byteLength);
+    return count;
+}
+
+uint32_t SkSecureReadBuffer::readPointArray(SkPoint* points) {
+    const uint32_t count = fReader.readU32();
+    const uint32_t byteLength = count * sizeof(SkPoint);
+    memcpy(points, fReader.skip(SkAlign4(byteLength)), byteLength);
+    return count;
+}
+
+uint32_t SkSecureReadBuffer::readScalarArray(SkScalar* values) {
+    const uint32_t count = fReader.readU32();
+    const uint32_t byteLength = count * sizeof(SkScalar);
+    memcpy(values, fReader.skip(SkAlign4(byteLength)), byteLength);
+    return count;
+}
+
+uint32_t SkSecureReadBuffer::getArrayCount() {
+    return *(uint32_t*)fReader.peek();
+}
+
+void SkSecureReadBuffer::readBitmap(SkBitmap* bitmap) {
+    const int width = this->readInt();
+    const int height = this->readInt();
+    const size_t length = this->readUInt();
+    // A size of zero means the SkBitmap was simply flattened.
+    if (length != 0) {
+        fReader.setError();
+    }
+    if (fReader.getError()) {
+        return;
+    }
+    bitmap->unflatten(*this);
+    if ((bitmap->width() != width) || (bitmap->height() != height)) {
+        fReader.setError();
+    }
+}
+
+SkTypeface* SkSecureReadBuffer::readTypeface() {
+
+    uint32_t index = fReader.readU32();
+    if (0 == index || index > (unsigned)fTFCount || fReader.getError()) {
+        if (index) {
+            SkDebugf("====== typeface index %d\n", index);
+        }
+        return NULL;
+    } else {
+        SkASSERT(fTFArray);
+        return fTFArray[index - 1];
+    }
+}
+
+SkFlattenable* SkSecureReadBuffer::readFlattenable() {
+    SkString string;
+    this->readString(&string);
+    if (fReader.getError()) {
+        return NULL;
+    }
+    SkFlattenable::Factory factory = SkFlattenable::NameToFactory(string.c_str());
+    if (NULL == factory) {
+        return NULL; // writer failed to give us the flattenable
+    }
+
+    // if we get here, factory may still be null, but if that is the case, the
+    // failure was ours, not the writer.
+    SkFlattenable* obj = NULL;
+    uint32_t sizeRecorded = fReader.readU32();
+    if (factory) {
+        uint32_t offset = fReader.offset();
+        obj = (*factory)(*this);
+        // check that we read the amount we expected
+        uint32_t sizeRead = fReader.offset() - offset;
+        if (sizeRecorded != sizeRead) {
+            // we could try to fix up the offset...
+            fReader.setError();
+            delete obj;
+            obj = NULL;
+        }
+    } else {
+        // we must skip the remaining data
+        fReader.skip(sizeRecorded);
+    }
+    return obj;
+}