Add support for bsdiff of file system metadata blocks

test_utils.h

 // Copyright (c) 2010 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 CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H__
 #define CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H__
 
 #include <set>
 #include <string>
 #include <vector>
 #include <gtest/gtest.h>
 #include "base/scoped_ptr.h"
+#include "base/string_util.h"

[petkov, 2010/12/10 00:46:55]

since you've touched the headers -- "new" style is use <> for the library
includes, sort them together with gtest and add blank lines...

[thieule, 2010/12/14 23:11:21]

Done.

 #include "update_engine/action.h"
 #include "update_engine/subprocess.h"
 #include "update_engine/utils.h"
 
 // These are some handy functions for unittests.
 
 namespace chromeos_update_engine {
 
 // Writes the data passed to path. The file at path will be overwritten if it
 // exists. Returns true on success, false otherwise.
@@ skipping 62 matching lines @@
   0xe8, 0x05, 0x08, 0xa1, 0x45, 0x70, 0x5b, 0x8c,
   0x39, 0x28, 0xab, 0xe9, 0x6b, 0x51, 0xd2, 0xcb,
   0x30, 0x04, 0xea, 0x7d, 0x2f, 0x6e, 0x6c, 0x3b,
   0x5f, 0x82, 0xd9, 0x5b, 0x89, 0x37, 0x65, 0x65,
   0xbe, 0x9f, 0xa3, 0x5d
 };
 
 const char* const kMountPath = "/tmp/UpdateEngineTests_mnt";
 }  // namespace {}
 
+// Creates an empty ext image.

[petkov, 2010/12/10 00:46:55]

ext2, ext3, ext4?

[thieule, 2010/12/14 23:11:21]

This is a little bit more involved than just here.  I'll do the ext3 to ext2
change in a separate CL.

+void CreateEmptyExtImageAtPath(const std::string& path,
+                               size_t size,
+                               int block_size);
+
 // Creates an ext image with some files in it. The paths creates are
 // returned in out_paths.
 void CreateExtImageAtPath(const std::string& path,
                           std::vector<std::string>* out_paths);
 
 // Verifies that for each path in paths, it exists in the filesystem under
 // parent. Also, verifies that no additional paths are present under parent.
 // Also tests properties of various files created by CreateExtImageAtPath().
 // Intentionally copies expected_paths.
 void VerifyAllPaths(const std::string& parent,
@@ skipping 99 matching lines @@
     }
     this->processor_->ActionComplete(this, kActionCodeSuccess);
   }
   static std::string StaticType() { return "ObjectCollectorAction"; }
   std::string Type() const { return StaticType(); }
   const T& object() const { return object_; }
  private:
   T object_;
 };
 
+class ScopedLoopMounter {
+ public:
+  explicit ScopedLoopMounter(const std::string& file_path,
+                             std::string* mnt_path,
+                             unsigned long flags) {
+    EXPECT_TRUE(utils::MakeTempDirectory("/tmp/mnt.XXXXXX", mnt_path));

[petkov, 2010/12/10 00:46:55]

lots of code for a header file. could you please move the implementation into
the .cc file?

[thieule, 2010/12/14 23:11:21]

Done.

+    dir_remover_.reset(new ScopedDirRemover(*mnt_path));
+
+    std::string loop_dev = GetUnusedLoopDevice();
+    EXPECT_EQ(0, system(StringPrintf("losetup %s %s", loop_dev.c_str(),
+                                     file_path.c_str()).c_str()));
+    loop_releaser_.reset(new ScopedLoopbackDeviceReleaser(loop_dev));
+
+    EXPECT_TRUE(utils::MountFilesystem(loop_dev, *mnt_path, flags));
+    unmounter_.reset(new ScopedFilesystemUnmounter(*mnt_path));
+  }
+ private:

[petkov, 2010/12/10 00:46:55]

blank line before private

[thieule, 2010/12/14 23:11:21]

Done.

+  scoped_ptr<ScopedDirRemover> dir_remover_;

[petkov, 2010/12/10 00:46:55]

i guess this is not new code but... is there any rule that says what order these
objects will be destructed in? if no rule, then random order is bad.

[thieule, 2010/12/14 23:11:21]

There is an explicit order that these objects must be destructed.  I've added a
comment to indicate such order.

+  scoped_ptr<ScopedLoopbackDeviceReleaser> loop_releaser_;
+  scoped_ptr<ScopedFilesystemUnmounter> unmounter_;
+};
+
 }  // namespace chromeos_update_engine
 
 #endif  // CHROMEOS_PLATFORM_UPDATE_ENGINE_TEST_UTILS_H__