Add the brotli compressor for bsdiff

Add a new compressor interface; and the brotli compressor which is
similar to the existing bz2 one.

Also add a new CompressorType argument to PatchWriter's init function;
this allows us to choose the right compressor based on the input option
in the future.

Bug: 34220646
Test:  Run bsdiff/bspatch with brotli compressor/decompressor over a
list of files from angler's system image. Make succeeds.
Change-Id: Id9a3db2d7d051dcb751a1fc362f4c3b9226e878b
diff --git a/brotli_compressor.cc b/brotli_compressor.cc
new file mode 100644
index 0000000..8238650
--- /dev/null
+++ b/brotli_compressor.cc
@@ -0,0 +1,93 @@
+// Copyright 2017 The Chromium OS 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 "bsdiff/brotli_compressor.h"
+
+#include "bsdiff/logging.h"
+
+using std::endl;
+
+namespace {
+// TODO(xunchang) set brotli compression parameters based on input options.
+const size_t kBufferSize = 1024 * 1024;
+const uint32_t kBrotliQuality = 11;
+const uint32_t kBrotliLgwin = 24;
+
+}  // namespace
+
+namespace bsdiff {
+
+BrotliCompressor::BrotliCompressor() : comp_buffer_(kBufferSize) {
+  brotli_encoder_state_ =
+      BrotliEncoderCreateInstance(nullptr, nullptr, nullptr);
+  if (!brotli_encoder_state_) {
+    LOG(ERROR) << "Failed to initialize brotli decoder state" << endl;
+  } else {
+    BrotliEncoderSetParameter(brotli_encoder_state_, BROTLI_PARAM_QUALITY,
+                              kBrotliQuality);
+    BrotliEncoderSetParameter(brotli_encoder_state_, BROTLI_PARAM_LGWIN,
+                              kBrotliLgwin);
+  }
+}
+
+BrotliCompressor::~BrotliCompressor() {
+  if (brotli_encoder_state_) {
+    BrotliEncoderDestroyInstance(brotli_encoder_state_);
+  }
+}
+
+bool BrotliCompressor::Write(const uint8_t* buf, size_t size) {
+  if (!brotli_encoder_state_)
+    return false;
+
+  const uint8_t* next_in = buf;
+  size_t avail_in = size;
+  while (avail_in > 0) {
+    size_t avail_out = kBufferSize;
+    uint8_t* next_out = comp_buffer_.buffer_data();
+    if (!BrotliEncoderCompressStream(
+            brotli_encoder_state_, BROTLI_OPERATION_PROCESS, &avail_in,
+            &next_in, &avail_out, &next_out, nullptr)) {
+      LOG(ERROR) << "BrotliCompressor failed to compress " << avail_in
+                 << " bytes of data." << endl;
+      return false;
+    }
+
+    uint64_t output_bytes = comp_buffer_.buffer_size() - avail_out;
+    if (output_bytes > 0) {
+      comp_buffer_.AddDataToChunks(output_bytes);
+    }
+  }
+  return true;
+}
+
+bool BrotliCompressor::Finish() {
+  if (!brotli_encoder_state_)
+    return false;
+
+  const uint8_t* next_in = nullptr;
+  size_t avail_in = 0;
+  while (!BrotliEncoderIsFinished(brotli_encoder_state_)) {
+    size_t avail_out = kBufferSize;
+    uint8_t* next_out = comp_buffer_.buffer_data();
+    if (!BrotliEncoderCompressStream(
+            brotli_encoder_state_, BROTLI_OPERATION_FINISH, &avail_in, &next_in,
+            &avail_out, &next_out, nullptr)) {
+      LOG(ERROR) << "BrotliCompressor failed to finish compression" << endl;
+      return false;
+    }
+
+    uint64_t output_bytes = comp_buffer_.buffer_size() - avail_out;
+    if (output_bytes > 0) {
+      comp_buffer_.AddDataToChunks(output_bytes);
+    }
+  }
+  return true;
+}
+
+const std::vector<uint8_t>& BrotliCompressor::GetCompressedData() {
+  return comp_buffer_.GetCompressedData();
+}
+
+}  // namespace bsdiff