Merge changes I9350157e,Ie450b279,Icc85d8b4

am: bfef6ef102

Change-Id: Ifb99ffacc3939fc15af6b00772e2e7b445006b22

.gitignore

@@ -4,11 +4,12 @@
 # any tracked files which get ignored after the change.
 #
 
-# Standard ignores
+# Ignore object files and backup files
 *.o
+*.so
 *~
 
 # Executables
-bsdiff
-bspatch
-unittests
+/bsdiff
+/bspatch
+/bsdiff_unittest

Android.bp

@@ -101,10 +101,10 @@ cc_test {
         "bspatch_unittest.cc",
         "extents_file_unittest.cc",
         "extents_unittest.cc",
+        "patch_writer_unittest.cc",
         "test_utils.cc",
         "testrunner.cc",
     ],
-    cflags: ["-DBSDIFF_TARGET_UNITTEST"],
     static_libs: [
         "libbsdiff",
         "libbspatch",
@@ -113,4 +113,9 @@ cc_test {
         "libdivsufsort",
         "libbz",
     ],
+    target: {
+        android: {
+            cflags: ["-DBSDIFF_TARGET_UNITTEST"],
+        },
+    },
 }

Makefile

@@ -53,6 +53,7 @@ bsdiff_common_unittests := \
     bspatch_unittest.cc \
     extents_file_unittest.cc \
     extents_unittest.cc \
+    patch_writer_unittest.cc \
     test_utils.cc \
     testrunner.cc
 

bsdiff.cc

@@ -118,12 +118,17 @@ int bsdiff(const char* old_filename, const char* new_filename,
 	return ret;
 }
 
-// Generate bsdiff patch from |old_buf| to |new_buf|, save the patch file to
-// |patch_filename|. Returns 0 on success.
-// |I_cache| can be used to cache the suffix array if the same |old_buf| is used
-// repeatedly, pass nullptr if not needed.
+// TODO(deymo): Deprecate this version of the interface and move all callers
+// to the underlying version using PatchWriterInterface instead. This allows
+// more flexible options including different encodings.
 int bsdiff(const u_char* old_buf, off_t oldsize, const u_char* new_buf,
            off_t newsize, const char* patch_filename, saidx_t** I_cache) {
+	BsdiffPatchWriter patch(patch_filename);
+	return bsdiff(old_buf, oldsize, new_buf, newsize, &patch, I_cache);
+}
+
+int bsdiff(const u_char* old_buf, off_t oldsize, const u_char* new_buf,
+           off_t newsize, PatchWriterInterface* patch, saidx_t** I_cache) {
 	saidx_t *I;
 	off_t scan,pos=0,len;
 	off_t lastscan,lastpos,lastoffset;
@@ -131,7 +136,6 @@ int bsdiff(const u_char* old_buf, off_t oldsize, const u_char* new_buf,
 	off_t s,Sf,lenf,Sb,lenb;
 	off_t overlap,Ss,lens;
 	off_t i;
-	BsdiffPatchWriter patch(old_buf, oldsize, new_buf, newsize);
 
 	if (I_cache && *I_cache) {
 		I = *I_cache;
@@ -139,13 +143,14 @@ int bsdiff(const u_char* old_buf, off_t oldsize, const u_char* new_buf,
 		if ((I=static_cast<saidx_t*>(malloc((oldsize+1)*sizeof(saidx_t))))==NULL)
 			err(1,NULL);
 
-		if (divsufsort(old_buf, I, oldsize)) err(1, "divsufsort");
+		// Note: divsufsort() fails when the passed size is 0 and old_buf is NULL.
+		if (oldsize > 0 && divsufsort(old_buf, I, oldsize)) err(1, "divsufsort");
 		if (I_cache)
 			*I_cache = I;
 	}
 
-	/* Create the patch file */
-	if (!patch.Open(patch_filename))
+	/* Initialize the patch file */
+	if (!patch->InitializeBuffers(old_buf, oldsize, new_buf, newsize))
 		return 1;
 
 	/* Compute the differences, writing ctrl as we go */
@@ -224,9 +229,10 @@ int bsdiff(const u_char* old_buf, off_t oldsize, const u_char* new_buf,
 				lenb-=lens;
 			};
 
-			if (!patch.AddControlEntry(ControlEntry(lenf,
-			                                        (scan - lenb) - (lastscan + lenf),
-			                                        (pos - lenb) - (lastpos + lenf))))
+			if (!patch->AddControlEntry(
+			        ControlEntry(lenf,
+			                     (scan - lenb) - (lastscan + lenf),
+			                     (pos - lenb) - (lastpos + lenf))))
 				errx(1, "Writing a control entry");
 
 			lastscan=scan-lenb;
@@ -234,7 +240,7 @@ int bsdiff(const u_char* old_buf, off_t oldsize, const u_char* new_buf,
 			lastoffset=pos-scan;
 		};
 	};
-	if (!patch.Close())
+	if (!patch->Close())
 		errx(1, "Closing the patch file");
 
 	if (I_cache == nullptr)

bsdiff.gyp

@@ -128,6 +128,7 @@
             'bspatch_unittest.cc',
             'extents_file_unittest.cc',
             'extents_unittest.cc',
+            'patch_writer_unittest.cc',
             'test_utils.cc',
           ],
         },

bsdiff_unittest.cc

@@ -5,58 +5,80 @@
 #include "bsdiff/bsdiff.h"
 
 #include <gtest/gtest.h>
+#include <algorithm>
+#include <random>
 #include <string>
 #include <vector>
 
-#include "bsdiff/test_utils.h"
+#include "bsdiff/fake_patch_writer.h"
 
-using test_utils::BsdiffPatchFile;
+namespace {
+
+// Generate deterministic random data in the output buffer. The buffer must be
+// already allocated with the desired size. The data generated depends on the
+// selected size.
+void GenerateRandomBuffer(std::vector<uint8_t>* buffer) {
+  std::minstd_rand prng(1234 + buffer->size());
+  std::generate(buffer->begin(), buffer->end(), prng);
+}
+
+}  // namespace
 
 namespace bsdiff {
 
 class BsdiffTest : public testing::Test {
  protected:
-  BsdiffTest()
-    : old_file_("bsdiff_oldfile.XXXXXX"),
-      new_file_("bsdiff_newfile.XXXXXX"),
-      patch_file_("bsdiff_patchfile.XXXXXX") {
-  }
-  ~BsdiffTest() override {}
+  BsdiffTest() = default;
+  ~BsdiffTest() override = default;
 
-  test_utils::ScopedTempFile old_file_;
-  test_utils::ScopedTempFile new_file_;
-  test_utils::ScopedTempFile patch_file_;
+  void RunBsdiff() {
+    EXPECT_EQ(0, bsdiff(old_file_.data(), old_file_.size(), new_file_.data(),
+                        new_file_.size(), &patch_writer_, nullptr));
+  }
+
+  std::vector<uint8_t> old_file_;
+  std::vector<uint8_t> new_file_;
+  FakePatchWriter patch_writer_;
 };
 
 // Check that a file with no changes has a very small patch (no extra data).
 TEST_F(BsdiffTest, EqualEmptyFiles) {
   // Empty old and new files.
-  EXPECT_EQ(0, bsdiff(old_file_.filename().c_str(),
-                      new_file_.filename().c_str(),
-                      patch_file_.filename().c_str()));
-  BsdiffPatchFile patch;
-  EXPECT_TRUE(patch.LoadFromFile(patch_file_.filename()));
-  EXPECT_TRUE(patch.IsValid());
+  RunBsdiff();
 
-  // An empty bz2 file will have 14 bytes.
-  EXPECT_EQ(14, patch.diff_len);
-  EXPECT_EQ(14U, patch.extra_len);
+  // No entries should be generated on an empty new file.
+  EXPECT_TRUE(patch_writer_.entries().empty());
 }
 
 TEST_F(BsdiffTest, EqualSmallFiles) {
   std::string some_text = "Hello world!";
-  std::vector<uint8_t> vec_some_text(some_text.begin(), some_text.end());
-  test_utils::WriteFile(old_file_.filename(), vec_some_text);
-  EXPECT_EQ(0, bsdiff(old_file_.filename().c_str(),
-                      new_file_.filename().c_str(),
-                      patch_file_.filename().c_str()));
-  BsdiffPatchFile patch;
-  EXPECT_TRUE(patch.LoadFromFile(patch_file_.filename()));
-  EXPECT_TRUE(patch.IsValid());
+  old_file_.insert(old_file_.begin(), some_text.begin(), some_text.end());
+  new_file_.insert(new_file_.begin(), some_text.begin(), some_text.end());
+  RunBsdiff();
 
-  // An empty bz2 file will have 14 bytes.
-  EXPECT_EQ(14, patch.diff_len);
-  EXPECT_EQ(14U, patch.extra_len);
+  EXPECT_EQ(1U, patch_writer_.entries().size());
+  ControlEntry entry = patch_writer_.entries()[0];
+  EXPECT_EQ(some_text.size(), entry.diff_size);
+  EXPECT_EQ(0U, entry.extra_size);
+}
+
+TEST_F(BsdiffTest, FileWithSmallErrorsTest) {
+  old_file_.resize(100);
+  GenerateRandomBuffer(&old_file_);
+  new_file_ = old_file_;
+  // Break a few bytes somewhere in the middle.
+  new_file_[20]++;
+  new_file_[30] += 2;
+  new_file_[31] += 2;
+
+  RunBsdiff();
+
+  // We expect that the result has only one entry with all in the diff stream
+  // since the two files are very similar.
+  EXPECT_EQ(1U, patch_writer_.entries().size());
+  ControlEntry entry = patch_writer_.entries()[0];
+  EXPECT_EQ(100U, entry.diff_size);
+  EXPECT_EQ(0U, entry.extra_size);
 }
 
 }  // namespace bsdiff

fake_patch_writer.h

@@ -0,0 +1,69 @@
+// 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.
+
+#ifndef _BSDIFF_FAKE_PATCH_WRITER_H_
+#define _BSDIFF_FAKE_PATCH_WRITER_H_
+
+#include <gtest/gtest.h>
+#include <vector>
+
+#include "bsdiff/patch_writer_interface.h"
+
+namespace bsdiff {
+
+// A fake PatchWriterInterface derived class with easy access to the data passed
+// to it.
+class FakePatchWriter : public PatchWriterInterface {
+ public:
+  FakePatchWriter() = default;
+  ~FakePatchWriter() override = default;
+
+  // PatchWriterInterface overrides.
+  bool InitializeBuffers(const uint8_t* old_buf,
+                         uint64_t old_size,
+                         const uint8_t* new_buf,
+                         uint64_t new_size) override {
+    EXPECT_FALSE(initialized_);
+    initialized_ = true;
+    new_size_ = new_size;
+    old_size_ = old_size;
+    return true;
+  }
+
+  bool AddControlEntry(const ControlEntry& entry) override {
+    EXPECT_TRUE(initialized_);
+    EXPECT_FALSE(closed_);
+    entries_.push_back(entry);
+    return true;
+  }
+
+  bool Close() override {
+    EXPECT_FALSE(closed_) << "Close() already called";
+    closed_ = true;
+    return true;
+  }
+
+  // Fake getter methods.
+  const std::vector<ControlEntry>& entries() const { return entries_; }
+
+  uint64_t new_size() const { return new_size_; }
+  uint64_t old_size() const { return old_size_; }
+
+ private:
+  // The list of ControlEntry passed to this class.
+  std::vector<ControlEntry> entries_;
+
+  // Whether this class was initialized.
+  bool initialized_{false};
+
+  // Whether the patch was closed.
+  bool closed_{false};
+
+  uint64_t new_size_;
+  uint64_t old_size_;
+};
+
+}  // namespace bsdiff
+
+#endif  // _BSDIFF_FAKE_PATCH_WRITER_H_

include/bsdiff/bsdiff.h

@@ -16,14 +16,21 @@
 #endif
 
 #include "bsdiff/common.h"
+#include "bsdiff/patch_writer_interface.h"
 
 namespace bsdiff {
 
+// Generate bsdiff patch from the |old_filename| file to the |new_filename|
+// file storing the resulting patch in a new |patch_filename| file.
 BSDIFF_EXPORT
 int bsdiff(const char* old_filename,
            const char* new_filename,
            const char* patch_filename);
 
+// Generate bsdiff patch from |old_buf| to |new_buf|, save the patch file to
+// |patch_filename|. Returns 0 on success.
+// |I_cache| can be used to cache the suffix array if the same |old_buf| is used
+// repeatedly, pass nullptr if not needed.
 BSDIFF_EXPORT
 int bsdiff(const u_char* old_buf,
            off_t oldsize,
@@ -32,6 +39,14 @@ int bsdiff(const u_char* old_buf,
            const char* patch_filename,
            saidx_t** I_cache);
 
+BSDIFF_EXPORT
+int bsdiff(const u_char* old_buf,
+           off_t oldsize,
+           const u_char* new_buf,
+           off_t newsize,
+           PatchWriterInterface* patch,
+           saidx_t** I_cache);
+
 }  // namespace bsdiff
 
 #endif  // _BSDIFF_BSDIFF_H_

include/bsdiff/patch_writer_interface.h

@@ -0,0 +1,58 @@
+// 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.
+
+#ifndef _BSDIFF_PATCH_WRITER_INTERFACE_H_
+#define _BSDIFF_PATCH_WRITER_INTERFACE_H_
+
+namespace bsdiff {
+
+struct ControlEntry {
+  ControlEntry(uint64_t diff_size,
+               uint64_t extra_size,
+               int64_t offset_increment)
+      : diff_size(diff_size),
+        extra_size(extra_size),
+        offset_increment(offset_increment) {}
+
+  // The number of bytes to copy from the source and diff stream.
+  uint64_t diff_size;
+
+  // The number of bytes to copy from the extra stream.
+  uint64_t extra_size;
+
+  // The value to add to the source pointer after patching from the diff stream.
+  int64_t offset_increment;
+};
+
+class PatchWriterInterface {
+ public:
+  virtual ~PatchWriterInterface() = default;
+
+  // Initialize the patch writer old and new files with the given buffers.
+  // These buffers are not copied into this class and must be valid until
+  // Close() is called. They will be used to encode the extra and diff streams
+  // when calling AddControlEntry(). Returns whether the initialization
+  // succeeded.
+  virtual bool InitializeBuffers(const uint8_t* old_buf,
+                                 uint64_t old_size,
+                                 const uint8_t* new_buf,
+                                 uint64_t new_size) = 0;
+
+  // Add a new control triplet entry to the patch. The |entry.diff_size| bytes
+  // for the diff stream and the |entry.extra_size| bytes for the extra stream
+  // will be computed and added to the corresponding streams in the patch.
+  // Returns whether the operation succeeded. The operation can fail if either
+  // the old or new files are referenced out of bounds.
+  virtual bool AddControlEntry(const ControlEntry& entry) = 0;
+
+  // Finalize the patch writing process and close the file.
+  virtual bool Close() = 0;
+
+ protected:
+  PatchWriterInterface() = default;
+};
+
+}  // namespace bsdiff
+
+#endif  // _BSDIFF_PATCH_WRITER_INTERFACE_H_

patch_writer.cc

@@ -31,10 +31,18 @@ void EncodeInt64(int64_t x, uint8_t* buf) {
 
 namespace bsdiff {
 
-bool BsdiffPatchWriter::Open(const std::string& patch_filename) {
-  fp_ = fopen(patch_filename.c_str(), "w");
+bool BsdiffPatchWriter::InitializeBuffers(const uint8_t* old_buf,
+                                          uint64_t old_size,
+                                          const uint8_t* new_buf,
+                                          uint64_t new_size) {
+  old_buf_ = old_buf;
+  old_size_ = old_size;
+  new_buf_ = new_buf;
+  new_size_ = new_size;
+
+  fp_ = fopen(patch_filename_.c_str(), "w");
   if (!fp_) {
-    LOG(ERROR) << "Opening " << patch_filename << endl;
+    LOG(ERROR) << "Opening " << patch_filename_ << endl;
     return false;
   }
   return true;

patch_writer.h

@@ -5,67 +5,41 @@
 #ifndef _BSDIFF_PATCH_WRITER_H_
 #define _BSDIFF_PATCH_WRITER_H_
 
-#include <stdio.h>
-
 #include <string>
 #include <vector>
 
-#include "bsdiff/common.h"
-#include "bz2_compressor.h"
+#include "bsdiff/bz2_compressor.h"
+#include "bsdiff/patch_writer_interface.h"
 
 namespace bsdiff {
 
-struct ControlEntry {
-  ControlEntry(uint64_t diff_size,
-               uint64_t extra_size,
-               int64_t offset_increment)
-      : diff_size(diff_size),
-        extra_size(extra_size),
-        offset_increment(offset_increment) {}
-
-  // The number of bytes to copy from the source and diff stream.
-  uint64_t diff_size;
-
-  // The number of bytes to copy from the extra stream.
-  uint64_t extra_size;
-
-  // The value to add to the source pointer after patching from the diff stream.
-  int64_t offset_increment;
-};
-
-class BsdiffPatchWriter {
+// A PatchWriterInterface class using the upstream's BSDIFF40 format: three
+// BZ2-compressors and a 32-byte header.
+class BsdiffPatchWriter : public PatchWriterInterface {
  public:
-  BsdiffPatchWriter(const uint8_t* old_buf,
-                    uint64_t old_size,
-                    const uint8_t* new_buf,
-                    uint64_t new_size)
-      : old_buf_(old_buf),
-        old_size_(old_size),
-        new_buf_(new_buf),
-        new_size_(new_size) {}
+  // Create the patch writer using the file |patch_filename| where the patch
+  // data will be written to.
+  explicit BsdiffPatchWriter(const std::string& patch_filename)
+      : patch_filename_(patch_filename) {}
 
-  // Create the file |patch_filename| where the patch will be written to.
-  bool Open(const std::string& patch_filename);
-
-  // Add a new control triplet entry to the patch. The |entry.diff_size| bytes
-  // for the diff stream and the |entry.extra_size| bytes for the extra stream
-  // will be computed and added to the corresponding streams in the patch.
-  // Returns whether the operation succeeded. The operation can fail if either
-  // the old or new files are referenced out of bounds.
-  bool AddControlEntry(const ControlEntry& entry);
-
-  bool Close();
+  // PatchWriterInterface overrides.
+  bool InitializeBuffers(const uint8_t* old_buf,
+                         uint64_t old_size,
+                         const uint8_t* new_buf,
+                         uint64_t new_size) override;
+  bool AddControlEntry(const ControlEntry& entry) override;
+  bool Close() override;
 
  private:
   // Write the BSDIFF patch header to the |fp_| given the size of the compressed
   // control block and the compressed diff block.
   bool WriteHeader(uint64_t ctrl_size, uint64_t diff_size);
 
-
-  const uint8_t* old_buf_;
-  uint64_t old_size_;
-  const uint8_t* new_buf_;
-  uint64_t new_size_;
+  // Old and new file buffers.
+  const uint8_t* old_buf_{nullptr};
+  uint64_t old_size_{0};
+  const uint8_t* new_buf_{nullptr};
+  uint64_t new_size_{0};
 
   // Bytes of the new_buf_ already written.
   uint64_t written_output_{0};
@@ -75,6 +49,7 @@ class BsdiffPatchWriter {
 
   // The current file we are writing to.
   FILE* fp_{nullptr};
+  std::string patch_filename_;
 
   // The three internal compressed streams.
   BZ2Compressor ctrl_stream_;

patch_writer_unittest.cc

@@ -0,0 +1,110 @@
+// 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/patch_writer.h"
+
+#include <gtest/gtest.h>
+
+#include "bsdiff/test_utils.h"
+
+namespace {
+
+// Generated with:
+// echo 'Hello World' | hexdump -v -e '"    " 12/1 "0x%02x, " "\n"'
+const uint8_t kHelloWorld[] = {
+    0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x57, 0x6f, 0x72, 0x6c, 0x64, 0x0a,
+};
+
+// Compressed empty file.
+// bzip2 -9 </dev/null | hexdump -v -e '"    " 7/1 "0x%02x, " "\n"'
+const uint8_t kCompressedEmpty[] = {0x42, 0x5a, 0x68, 0x39, 0x17, 0x72, 0x45,
+                                    0x38, 0x50, 0x90, 0x00, 0x00, 0x00, 0x00};
+
+// echo 'Hello World' | bzip2 -9 | hexdump -v -e '"    " 12/1 "0x%02x, " "\n"'
+const uint8_t kCompressedHelloWorld[] = {
+    0x42, 0x5a, 0x68, 0x39, 0x31, 0x41, 0x59, 0x26, 0x53, 0x59, 0xd8, 0x72,
+    0x01, 0x2f, 0x00, 0x00, 0x01, 0x57, 0x80, 0x00, 0x10, 0x40, 0x00, 0x00,
+    0x40, 0x00, 0x80, 0x06, 0x04, 0x90, 0x00, 0x20, 0x00, 0x22, 0x06, 0x86,
+    0xd4, 0x20, 0xc9, 0x88, 0xc7, 0x69, 0xe8, 0x28, 0x1f, 0x8b, 0xb9, 0x22,
+    0x9c, 0x28, 0x48, 0x6c, 0x39, 0x00, 0x97, 0x80,
+};
+
+// Compressed a buffer of zeros of the same length of the kHelloWorld.
+// head -c `echo 'Hello World' | wc -c` /dev/zero | bzip2 -9 |
+//   hexdump -v -e '"    " 10/1 "0x%02x, " "\n"'
+const uint8_t kCompressedZeros[] = {
+    0x42, 0x5a, 0x68, 0x39, 0x31, 0x41, 0x59, 0x26, 0x53, 0x59,
+    0xf6, 0x63, 0xab, 0xde, 0x00, 0x00, 0x00, 0x40, 0x00, 0x40,
+    0x40, 0x20, 0x00, 0x21, 0x00, 0x82, 0x83, 0x17, 0x72, 0x45,
+    0x38, 0x50, 0x90, 0xf6, 0x63, 0xab, 0xde,
+};
+
+}  // namespace
+
+namespace bsdiff {
+
+class BsdiffPatchWriterTest : public testing::Test {
+ protected:
+  test_utils::ScopedTempFile patch_file_{"bsdiff_newfile.XXXXXX"};
+  BsdiffPatchWriter patch_writer_{patch_file_.filename()};
+};
+
+TEST_F(BsdiffPatchWriterTest, CreateEmptyPatchTest) {
+  EXPECT_TRUE(patch_writer_.InitializeBuffers(nullptr, 0, nullptr, 0));
+  EXPECT_TRUE(patch_writer_.Close());
+
+  test_utils::BsdiffPatchFile patch;
+  EXPECT_TRUE(patch.LoadFromFile(patch_file_.filename()));
+  EXPECT_TRUE(patch.IsValid());
+
+  // An empty bz2 file will have 14 bytes.
+  EXPECT_EQ(sizeof(kCompressedEmpty), static_cast<uint64_t>(patch.diff_len));
+  EXPECT_EQ(sizeof(kCompressedEmpty), patch.extra_len);
+}
+
+TEST_F(BsdiffPatchWriterTest, AllInExtraStreamTest) {
+  EXPECT_TRUE(patch_writer_.InitializeBuffers(
+      nullptr, 0, kHelloWorld, sizeof(kHelloWorld)));
+  // Write to the extra stream in two parts: first 5 bytes, then the rest.
+  EXPECT_TRUE(patch_writer_.AddControlEntry(ControlEntry(0, 5, 0)));
+  EXPECT_TRUE(patch_writer_.AddControlEntry(
+      ControlEntry(0, sizeof(kHelloWorld) - 5, 0)));
+  EXPECT_TRUE(patch_writer_.Close());
+
+  test_utils::BsdiffPatchFile patch;
+  EXPECT_TRUE(patch.LoadFromFile(patch_file_.filename()));
+  EXPECT_TRUE(patch.IsValid());
+  EXPECT_EQ(patch.bz2_diff,
+            std::vector<uint8_t>(kCompressedEmpty,
+                                 kCompressedEmpty + sizeof(kCompressedEmpty)));
+  EXPECT_EQ(patch.bz2_extra,
+            std::vector<uint8_t>(
+                kCompressedHelloWorld,
+                kCompressedHelloWorld + sizeof(kCompressedHelloWorld)));
+
+  EXPECT_EQ(static_cast<int64_t>(sizeof(kHelloWorld)), patch.new_file_len);
+}
+
+TEST_F(BsdiffPatchWriterTest, AllInDiffStreamTest) {
+  EXPECT_TRUE(patch_writer_.InitializeBuffers(
+      kHelloWorld, sizeof(kHelloWorld), kHelloWorld, sizeof(kHelloWorld)));
+  // Write to the extra stream in two parts: first 5 bytes, then the rest.
+  EXPECT_TRUE(
+      patch_writer_.AddControlEntry(ControlEntry(sizeof(kHelloWorld), 0, 0)));
+  EXPECT_TRUE(patch_writer_.Close());
+
+  test_utils::BsdiffPatchFile patch;
+  EXPECT_TRUE(patch.LoadFromFile(patch_file_.filename()));
+  EXPECT_TRUE(patch.IsValid());
+  EXPECT_EQ(patch.bz2_extra,
+            std::vector<uint8_t>(kCompressedEmpty,
+                                 kCompressedEmpty + sizeof(kCompressedEmpty)));
+  EXPECT_EQ(patch.bz2_diff,
+            std::vector<uint8_t>(kCompressedZeros,
+                                 kCompressedZeros + sizeof(kCompressedZeros)));
+
+  EXPECT_EQ(static_cast<int64_t>(sizeof(kHelloWorld)), patch.new_file_len);
+}
+
+}  // namespace bsdiff