1 files changed, 412 insertions, 0 deletions
diff --git a/courgette/ensemble_apply.cc b/courgette/ensemble_apply.cc
new file mode 100644
index 0000000..5a9edfd4
--- /dev/null
+++ b/courgette/ensemble_apply.cc
@@ -0,0 +1,412 @@
+// Copyright (c) 2009 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// This file contains the code to apply a Courgette patch.
+
+#include "courgette/ensemble.h"
+
+#include "base/basictypes.h"
+#include "base/file_util.h"
+#include "base/logging.h"
+
+#include "courgette/crc.h"
+#include "courgette/image_info.h"
+#include "courgette/region.h"
+#include "courgette/streams.h"
+#include "courgette/simple_delta.h"
+#include "courgette/win32_x86_patcher.h"
+
+namespace courgette {
+
+// EnsemblePatchApplication is all the logic and data required to apply the
+// multi-stage patch.
+class EnsemblePatchApplication {
+ public:
+  EnsemblePatchApplication();
+  ~EnsemblePatchApplication();
+
+  Status ReadHeader(SourceStream* header_stream);
+
+  Status InitBase(const Region& region);
+
+  Status ValidateBase();
+
+  Status ReadInitialParameters(SourceStream* initial_parameters);
+
+  Status PredictTransformParameters(SinkStreamSet* predicted_parameters);
+
+  Status SubpatchTransformParameters(SinkStreamSet* prediction,
+                                     SourceStream* correction,
+                                     SourceStreamSet* corrected_parameters);
+
+  Status TransformUp(SourceStreamSet* parameters,
+                     SinkStreamSet* transformed_elements);
+
+  Status SubpatchTransformedElements(SinkStreamSet* elements,
+                                     SourceStream* correction,
+                                     SourceStreamSet* corrected_elements);
+
+  Status TransformDown(SourceStreamSet* transformed_elements,
+                       SinkStream* basic_elements);
+
+  Status SubpatchFinalOutput(SourceStream* original,
+                             SourceStream* correction,
+                             SinkStream* corrected_ensemble);
+
+ private:
+  Status SubpatchStreamSets(SinkStreamSet* predicted_items,
+                            SourceStream* correction,
+                            SourceStreamSet* corrected_items,
+                            SinkStream* corrected_items_storage);
+
+  Region base_region_;       // Location of in-memory copy of 'old' version.
+
+  uint32 source_checksum_;
+  uint32 target_checksum_;
+
+  std::vector<TransformationPatcher*> patchers_;
+
+  SinkStream corrected_parameters_storage_;
+  SinkStream corrected_elements_storage_;
+
+  DISALLOW_COPY_AND_ASSIGN(EnsemblePatchApplication);
+};
+
+EnsemblePatchApplication::EnsemblePatchApplication()
+    : source_checksum_(0), target_checksum_(0) {
+}
+
+EnsemblePatchApplication::~EnsemblePatchApplication() {
+  for (size_t i = 0;  i < patchers_.size();  ++i) {
+    delete patchers_[i];
+  }
+}
+
+Status EnsemblePatchApplication::ReadHeader(SourceStream* header_stream) {
+  uint32 magic;
+  if (!header_stream->ReadVarint32(&magic))
+    return C_BAD_ENSEMBLE_MAGIC;
+
+  if (magic != CourgettePatchFile::kMagic)
+    return C_BAD_ENSEMBLE_MAGIC;
+
+  uint32 version;
+  if (!header_stream->ReadVarint32(&version))
+    return C_BAD_ENSEMBLE_VERSION;
+
+  if (version != CourgettePatchFile::kVersion)
+    return C_BAD_ENSEMBLE_VERSION;
+
+  if (!header_stream->ReadVarint32(&source_checksum_))
+    return C_BAD_ENSEMBLE_HEADER;
+
+  if (!header_stream->ReadVarint32(&target_checksum_))
+    return C_BAD_ENSEMBLE_HEADER;
+
+  return C_OK;
+}
+
+Status EnsemblePatchApplication::InitBase(const Region& region) {
+  base_region_.assign(region);
+  return C_OK;
+}
+
+Status EnsemblePatchApplication::ValidateBase() {
+  uint32 checksum = CalculateCrc(base_region_.start(), base_region_.length());
+  if (source_checksum_ != checksum)
+    return C_BAD_ENSEMBLE_CRC;
+
+  return C_OK;
+}
+
+Status EnsemblePatchApplication::ReadInitialParameters(
+    SourceStream* transformation_parameters) {
+  uint32 number_of_transformations = 0;
+  if (!transformation_parameters->ReadVarint32(&number_of_transformations))
+    return C_BAD_ENSEMBLE_HEADER;
+
+  for (size_t i = 0;  i < number_of_transformations;  ++i) {
+    uint32 kind;
+    if (!transformation_parameters->ReadVarint32(&kind))
+      return C_BAD_ENSEMBLE_HEADER;
+
+    if (kind == CourgettePatchFile::T_COURGETTE_WIN32_X86) {
+      TransformationPatcher* patcher =
+          new CourgetteWin32X86Patcher(base_region_);
+      patchers_.push_back(patcher);
+    } else {
+      return C_BAD_ENSEMBLE_HEADER;
+    }
+  }
+
+  for (size_t i = 0;  i < patchers_.size();  ++i) {
+    Status status = patchers_[i]->Init(transformation_parameters);
+    if (status != C_OK)
+      return status;
+  }
+
+  // All transformation_parameters should have been consumed by the above loop.
+  if (!transformation_parameters->Empty())
+    return C_BAD_ENSEMBLE_HEADER;
+
+  return C_OK;
+}
+
+Status EnsemblePatchApplication::PredictTransformParameters(
+    SinkStreamSet* all_predicted_parameters) {
+  for (size_t i = 0;  i < patchers_.size();  ++i) {
+    SinkStreamSet single_predicted_parameters;
+    Status status =
+        patchers_[i]->PredictTransformParameters(&single_predicted_parameters);
+    if (status != C_OK)
+      return status;
+    if (!all_predicted_parameters->WriteSet(&single_predicted_parameters))
+      return C_STREAM_ERROR;
+  }
+  return C_OK;
+}
+
+Status EnsemblePatchApplication::SubpatchTransformParameters(
+    SinkStreamSet* predicted_parameters,
+    SourceStream* correction,
+    SourceStreamSet* corrected_parameters) {
+  return SubpatchStreamSets(predicted_parameters,
+                            correction,
+                            corrected_parameters,
+                            &corrected_parameters_storage_);
+}
+
+Status EnsemblePatchApplication::TransformUp(
+    SourceStreamSet* parameters,
+    SinkStreamSet* transformed_elements) {
+  for (size_t i = 0;  i < patchers_.size();  ++i) {
+    SourceStreamSet single_parameters;
+    if (!parameters->ReadSet(&single_parameters))
+      return C_STREAM_ERROR;
+    SinkStreamSet single_transformed_element;
+    Status status = patchers_[i]->Transform(&single_parameters,
+                                            &single_transformed_element);
+    if (status != C_OK)
+      return status;
+    if (!single_parameters.Empty())
+      return C_STREAM_NOT_CONSUMED;
+    if (!transformed_elements->WriteSet(&single_transformed_element))
+      return C_STREAM_ERROR;
+  }
+
+  if (!parameters->Empty())
+    return C_STREAM_NOT_CONSUMED;
+  return C_OK;
+}
+
+Status EnsemblePatchApplication::SubpatchTransformedElements(
+    SinkStreamSet* predicted_elements,
+    SourceStream* correction,
+    SourceStreamSet* corrected_elements) {
+  return SubpatchStreamSets(predicted_elements,
+                            correction,
+                            corrected_elements,
+                            &corrected_elements_storage_);
+}
+
+Status EnsemblePatchApplication::TransformDown(
+    SourceStreamSet* transformed_elements,
+    SinkStream* basic_elements) {
+  // Construct blob of original input followed by reformed elements.
+
+  // The original input:
+  basic_elements->Write(base_region_.start(), base_region_.length());
+
+  for (size_t i = 0;  i < patchers_.size();  ++i) {
+    SourceStreamSet single_corrected_element;
+    if (!transformed_elements->ReadSet(&single_corrected_element))
+      return C_STREAM_ERROR;
+    Status status = patchers_[i]->Reform(&single_corrected_element,
+                                         basic_elements);
+    if (status != C_OK)
+      return status;
+    if (!single_corrected_element.Empty())
+      return C_STREAM_NOT_CONSUMED;
+  }
+
+  if (!transformed_elements->Empty())
+    return C_STREAM_NOT_CONSUMED;
+
+  return C_OK;
+}
+
+Status EnsemblePatchApplication::SubpatchFinalOutput(
+    SourceStream* original,
+    SourceStream* correction,
+    SinkStream* corrected_ensemble) {
+  Status delta_status = ApplySimpleDelta(original, correction,
+                                         corrected_ensemble);
+  if (delta_status != C_OK)
+    return delta_status;
+
+  if (CalculateCrc(corrected_ensemble->Buffer(),
+                   corrected_ensemble->Length()) != target_checksum_)
+    return C_BAD_ENSEMBLE_CRC;
+
+  return C_OK;
+}
+
+Status EnsemblePatchApplication::SubpatchStreamSets(
+    SinkStreamSet* predicted_items,
+    SourceStream* correction,
+    SourceStreamSet* corrected_items,
+    SinkStream* corrected_items_storage) {
+  SinkStream linearized_predicted_items;
+  if (!predicted_items->CopyTo(&linearized_predicted_items))
+    return C_STREAM_ERROR;
+
+  SourceStream prediction;
+  prediction.Init(linearized_predicted_items);
+
+  Status status = ApplySimpleDelta(&prediction,
+                                   correction,
+                                   corrected_items_storage);
+  if (status != C_OK)
+    return status;
+
+  if (!corrected_items->Init(corrected_items_storage->Buffer(),
+                             corrected_items_storage->Length()))
+    return C_STREAM_ERROR;
+
+  return C_OK;
+}
+
+Status ApplyEnsemblePatch(SourceStream* base,
+                          SourceStream* patch,
+                          SinkStream* output) {
+  Status status;
+  EnsemblePatchApplication patch_process;
+
+  status = patch_process.ReadHeader(patch);
+  if (status != C_OK)
+    return status;
+
+  status = patch_process.InitBase(Region(base->Buffer(), base->Remaining()));
+  if (status != C_OK)
+    return status;
+
+  status = patch_process.ValidateBase();
+  if (status != C_OK)
+    return status;
+
+  // The rest of the patch stream is a StreamSet.
+  SourceStreamSet patch_streams;
+  patch_streams.Init(patch);
+
+  SourceStream* transformation_descriptions     = patch_streams.stream(0);
+  SourceStream* parameter_correction            = patch_streams.stream(1);
+  SourceStream* transformed_elements_correction = patch_streams.stream(2);
+  SourceStream* ensemble_correction             = patch_streams.stream(3);
+
+  status = patch_process.ReadInitialParameters(transformation_descriptions);
+  if (status != C_OK)
+    return status;
+
+  SinkStreamSet predicted_parameters;
+  status = patch_process.PredictTransformParameters(&predicted_parameters);
+  if (status != C_OK)
+    return status;
+
+  SourceStreamSet corrected_parameters;
+  status = patch_process.SubpatchTransformParameters(&predicted_parameters,
+                                                     parameter_correction,
+                                                     &corrected_parameters);
+  if (status != C_OK)
+    return status;
+
+  SinkStreamSet transformed_elements;
+  status = patch_process.TransformUp(&corrected_parameters,
+                                     &transformed_elements);
+  if (status != C_OK)
+    return status;
+
+  SourceStreamSet corrected_transformed_elements;
+  status = patch_process.SubpatchTransformedElements(
+          &transformed_elements,
+          transformed_elements_correction,
+          &corrected_transformed_elements);
+  if (status != C_OK)
+    return status;
+
+  SinkStream original_ensemble_and_corrected_base_elements;
+  status = patch_process.TransformDown(
+      &corrected_transformed_elements,
+      &original_ensemble_and_corrected_base_elements);
+  if (status != C_OK)
+    return status;
+
+  SourceStream final_patch_prediction;
+  final_patch_prediction.Init(original_ensemble_and_corrected_base_elements);
+  status = patch_process.SubpatchFinalOutput(&final_patch_prediction,
+                                             ensemble_correction, output);
+  if (status != C_OK)
+    return status;
+
+  return C_OK;
+}
+
+Status ApplyEnsemblePatch(const wchar_t* old_file_name,
+                          const wchar_t* patch_file_name,
+                          const wchar_t* new_file_name) {
+  Status status;
+
+  // First read enough of the patch file to validate the header is well-formed.
+  // A few varint32 numbers should fit in 100.
+  FilePath patch_file_path(patch_file_name);
+  const int BIG_ENOUGH_FOR_HEADER = 100;
+  char buffer[BIG_ENOUGH_FOR_HEADER];
+  int read_count =
+      file_util::ReadFile(patch_file_path, buffer, sizeof(buffer));
+  if (read_count < 0)
+    return C_READ_OPEN_ERROR;
+
+  // 'Dry-run' the first step of the patch process to validate format of header.
+  SourceStream patch_header_stream;
+  patch_header_stream.Init(buffer, read_count);
+  EnsemblePatchApplication patch_process;
+  status = patch_process.ReadHeader(&patch_header_stream);
+  if (status != C_OK)
+    return status;
+
+  // Header smells good so read the whole patch file for real.
+  std::string patch_file_buffer;
+  if (!file_util::ReadFileToString(patch_file_path, &patch_file_buffer))
+    return C_READ_ERROR;
+
+  // Read the old_file.
+  FilePath old_file_path(old_file_name);
+  std::string old_file_buffer;
+  if (!file_util::ReadFileToString(old_file_path, &old_file_buffer))
+    return C_READ_ERROR;
+
+  // Apply patch on streams.
+  SourceStream old_source_stream;
+  SourceStream patch_source_stream;
+  old_source_stream.Init(old_file_buffer);
+  patch_source_stream.Init(patch_file_buffer);
+  SinkStream new_sink_stream;
+  status = ApplyEnsemblePatch(&old_source_stream, &patch_source_stream,
+                              &new_sink_stream);
+
+  // Write the patched data to |new_file_name|.
+  FilePath new_file_path(new_file_name);
+  int written =
+      file_util::WriteFile(
+          new_file_path,
+          reinterpret_cast<const char*>(new_sink_stream.Buffer()),
+          new_sink_stream.Length());
+  if (written == -1)
+    return C_WRITE_OPEN_ERROR;
+  if (written != new_sink_stream.Length())
+    return C_WRITE_ERROR;
+
+  return C_OK;
+}
+
+}  // namespace