Add support for compression filters in the mojo dart:io

mojo/dart/embedder/io/filter.cc

+// 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.
+
+#include "mojo/dart/embedder/io/filter.h"
+
+namespace mojo {
+namespace dart {
+
+const int kZLibFlagUseGZipHeader = 16;
+const int kZLibFlagAcceptAnyHeader = 32;
+
+static const int kFilterPointerNativeField = 0;
+
+Dart_Handle Filter::SetFilterPointerNativeField(Dart_Handle filter,
+                                                Filter* filter_pointer) {
+  return Dart_SetNativeInstanceField(
+      filter,
+      kFilterPointerNativeField,
+      reinterpret_cast<intptr_t>(filter_pointer));
+}
+
+
+Dart_Handle Filter::GetFilterPointerNativeField(Dart_Handle filter,
+                                                Filter** filter_pointer) {
+  return Dart_GetNativeInstanceField(
+      filter,
+      kFilterPointerNativeField,
+      reinterpret_cast<intptr_t*>(filter_pointer));
+}
+
+
+ZLibDeflateFilter::~ZLibDeflateFilter() {
+  delete[] dictionary_;
+  delete[] current_buffer_;
+  if (initialized()) deflateEnd(&stream_);
+}
+
+
+bool ZLibDeflateFilter::Init() {
+  int window_bits = window_bits_;
+  if (raw_) {
+    window_bits = -window_bits;
+  } else if (gzip_) {
+    window_bits += kZLibFlagUseGZipHeader;
+  }
+  stream_.next_in = Z_NULL;
+  stream_.zalloc = Z_NULL;
+  stream_.zfree = Z_NULL;
+  stream_.opaque = Z_NULL;
+  int result = deflateInit2(&stream_, level_, Z_DEFLATED, window_bits,
+                            mem_level_, strategy_);
+  if (result != Z_OK) {
+    return false;
+  }
+  if (dictionary_ != NULL && !gzip_ && !raw_) {
+    result = deflateSetDictionary(&stream_, dictionary_, dictionary_length_);
+    delete[] dictionary_;
+    dictionary_ = NULL;
+    if (result != Z_OK) {
+      return false;
+    }
+  }
+  set_initialized(true);
+  return true;
+}
+
+
+bool ZLibDeflateFilter::Process(uint8_t* data, intptr_t length) {
+  if (current_buffer_ != NULL) return false;
+  stream_.avail_in = length;
+  stream_.next_in = current_buffer_ = data;
+  return true;
+}
+
+intptr_t ZLibDeflateFilter::Processed(uint8_t* buffer,
+                                      intptr_t length,
+                                      bool flush,
+                                      bool end) {
+  stream_.avail_out = length;
+  stream_.next_out = buffer;
+  bool error = false;
+  switch (deflate(&stream_,
+                  end ? Z_FINISH : flush ? Z_SYNC_FLUSH : Z_NO_FLUSH)) {
+    case Z_STREAM_END:
+    case Z_BUF_ERROR:
+    case Z_OK: {
+      intptr_t processed = length - stream_.avail_out;
+      if (processed == 0) {
+        break;
+      }
+      return processed;
+    }
+
+    default:
+    case Z_STREAM_ERROR:
+        error = true;
+  }
+
+  delete[] current_buffer_;
+  current_buffer_ = NULL;
+  // Either 0 Byte processed or error
+  return error ? -1 : 0;
+}
+
+
+ZLibInflateFilter::~ZLibInflateFilter() {
+  delete[] dictionary_;
+  delete[] current_buffer_;
+  if (initialized()) inflateEnd(&stream_);
+}
+
+
+bool ZLibInflateFilter::Init() {
+  int window_bits = raw_ ?
+      -window_bits_ :
+      window_bits_ | kZLibFlagAcceptAnyHeader;
+
+  stream_.next_in = Z_NULL;
+  stream_.avail_in = 0;
+  stream_.zalloc = Z_NULL;
+  stream_.zfree = Z_NULL;
+  stream_.opaque = Z_NULL;
+  int result = inflateInit2(&stream_, window_bits);
+  if (result != Z_OK) {
+    return false;
+  }
+  set_initialized(true);
+  return true;
+}
+
+
+bool ZLibInflateFilter::Process(uint8_t* data, intptr_t length) {
+  if (current_buffer_ != NULL) return false;
+  stream_.avail_in = length;
+  stream_.next_in = current_buffer_ = data;
+  return true;
+}
+
+
+intptr_t ZLibInflateFilter::Processed(uint8_t* buffer,
+                                      intptr_t length,
+                                      bool flush,
+                                      bool end) {
+  stream_.avail_out = length;
+  stream_.next_out = buffer;
+  bool error = false;
+  int v;
+  switch (v = inflate(&stream_,
+                  end ? Z_FINISH : flush ? Z_SYNC_FLUSH : Z_NO_FLUSH)) {
+    case Z_STREAM_END:
+    case Z_BUF_ERROR:
+    case Z_OK: {
+      intptr_t processed = length - stream_.avail_out;
+      if (processed == 0) {
+        break;
+      }
+      return processed;
+    }
+
+    case Z_NEED_DICT:
+      if (dictionary_ == NULL) {
+        error = true;
+      } else {
+        int result = inflateSetDictionary(&stream_, dictionary_,
+                                          dictionary_length_);
+        delete[] dictionary_;
+        dictionary_ = NULL;
+        error = result != Z_OK;
+      }
+      if (error) {
+        break;
+      } else {
+        return Processed(buffer, length, flush, end);
+      }
+
+    default:
+    case Z_MEM_ERROR:
+    case Z_DATA_ERROR:
+    case Z_STREAM_ERROR:
+      error = true;
+  }
+
+  delete[] current_buffer_;
+  current_buffer_ = NULL;
+  // Either 0 Byte processed or error
+  return error ? -1 : 0;
+}
+
+}  // namespace dart
+}  // namespace mojo