Add support for compression filters in the mojo dart:io

mojo/dart/embedder/io/filter.h

+// Copyright 2016 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.
+
+#ifndef MOJO_DART_EMBEDDER_IO_FILTER_H_
+#define MOJO_DART_EMBEDDER_IO_FILTER_H_
+
+#include "dart/runtime/include/dart_api.h"
+#include "mojo/public/cpp/system/macros.h"
+#include "third_party/zlib/zlib.h"
+
+namespace mojo {
+namespace dart {
+
+class Filter {
+ public:
+  virtual ~Filter() {}
+
+  virtual bool Init() = 0;
+
+  /**
+   * On a successful call to Process, Process will take ownership of data. On
+   * successive calls to either Processed or ~Filter, data will be freed with
+   * a delete[] call.
+   */
+  virtual bool Process(uint8_t* data, intptr_t length) = 0;
+  virtual intptr_t Processed(uint8_t* buffer, intptr_t length, bool finish,
+                             bool end) = 0;
+
+  static Dart_Handle SetFilterPointerNativeField(Dart_Handle filter,
+                                                 Filter* filter_pointer);
+  static Dart_Handle GetFilterPointerNativeField(Dart_Handle filter,
+                                                 Filter** filter_pointer);
+
+  bool initialized() const { return initialized_; }
+  void set_initialized(bool value) { initialized_ = value; }
+  uint8_t* processed_buffer() { return processed_buffer_; }
+  intptr_t processed_buffer_size() const { return kFilterBufferSize; }
+
+ protected:
+  Filter() : initialized_(false) {}
+
+ private:
+  static const intptr_t kFilterBufferSize = 65536;
+  uint8_t processed_buffer_[kFilterBufferSize];
+  bool initialized_;
+
+  MOJO_DISALLOW_COPY_AND_ASSIGN(Filter);
+};
+
+class ZLibDeflateFilter : public Filter {
+ public:
+  ZLibDeflateFilter(bool gzip, int32_t level, int32_t window_bits,
+                    int32_t mem_level, int32_t strategy,
+                    uint8_t* dictionary, intptr_t dictionary_length, bool raw)
+      : gzip_(gzip), level_(level), window_bits_(window_bits),
+        mem_level_(mem_level), strategy_(strategy), dictionary_(dictionary),
+        dictionary_length_(dictionary_length), raw_(raw), current_buffer_(NULL)
+    {}
+  virtual ~ZLibDeflateFilter();
+
+  virtual bool Init();
+  virtual bool Process(uint8_t* data, intptr_t length);
+  virtual intptr_t Processed(uint8_t* buffer, intptr_t length, bool finish,
+                             bool end);
+
+ private:
+  const bool gzip_;
+  const int32_t level_;
+  const int32_t window_bits_;
+  const int32_t mem_level_;
+  const int32_t strategy_;
+  uint8_t* dictionary_;
+  const intptr_t dictionary_length_;
+  const bool raw_;
+  uint8_t* current_buffer_;
+  z_stream stream_;
+
+  MOJO_DISALLOW_COPY_AND_ASSIGN(ZLibDeflateFilter);
+};
+
+class ZLibInflateFilter : public Filter {
+ public:
+  ZLibInflateFilter(int32_t window_bits, uint8_t* dictionary,
+                    intptr_t dictionary_length, bool raw)
+      : window_bits_(window_bits), dictionary_(dictionary),
+        dictionary_length_(dictionary_length), raw_(raw), current_buffer_(NULL)
+    {}
+  virtual ~ZLibInflateFilter();
+
+  virtual bool Init();
+  virtual bool Process(uint8_t* data, intptr_t length);
+  virtual intptr_t Processed(uint8_t* buffer, intptr_t length, bool finish,
+                             bool end);
+
+ private:
+  const int32_t window_bits_;
+  uint8_t* dictionary_;
+  const intptr_t dictionary_length_;
+  const bool raw_;
+  uint8_t* current_buffer_;
+  z_stream stream_;
+
+  MOJO_DISALLOW_COPY_AND_ASSIGN(ZLibInflateFilter);
+};
+
+}  // namespace dart
+}  // namespace mojo
+
+#endif  // MOJO_DART_EMBEDDER_IO_FILTER_H_