media: Verify CDM Host files

content/common/media/cdm_host_files.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 CONTENT_COMMON_MEDIA_CDM_HOST_FILES_H_
+#define CONTENT_COMMON_MEDIA_CDM_HOST_FILES_H_
+
+#include <map>
+#include <memory>
+#include <vector>
+
+#include "base/files/file.h"
+#include "base/files/file_path.h"
+#include "base/lazy_instance.h"
+#include "base/logging.h"
+#include "base/memory/ptr_util.h"
+#include "base/native_library.h"
+#include "base/path_service.h"
+#include "build/build_config.h"
+#include "content/common/media/cdm_host_file.h"
+#include "content/common/pepper_plugin_list.h"
+#include "content/public/common/pepper_plugin_info.h"
+#include "media/cdm/cdm_paths.h"
+#include "media/cdm/content_decryption_module_ext.h"
+
+// On systems that use the zygote process to spawn child processes, we must
+// open files in the zygote process.
+#if defined(OS_POSIX) && !defined(OS_NACL) && !defined(OS_MACOSX) && \

[Greg K, 2016/12/16 22:10:41]

Is it simpler to just say defined(OS_LINUX)? Do another other systems use a
zygote? Note that OS_LINUX is true for OS_CHROMEOS.

[xhwang, 2016/12/16 22:30:15]

Good question. This was what I originally did. But I wasn't sure due to this
code:

https://cs.chromium.org/chromium/src/content/app/content_main_runner.cc?rcl=0...

I was about to ask you about this but then I "felt" I found the solution, which
is where this code is coming/copied from:

https://cs.chromium.org/chromium/src/base/metrics/field_trial.cc?rcl=0&l=26

[Greg K, 2016/12/16 22:34:41]

You're right. I looked at the definition of OS_POSIX and it's a lot more
complicated than just Linux, and Mac:

// For access to standard POSIXish features, use OS_POSIX instead of a
// more specific macro.
#if defined(OS_MACOSX) || defined(OS_LINUX) || defined(OS_FREEBSD) ||     \
    defined(OS_NETBSD) || defined(OS_OPENBSD) || defined(OS_SOLARIS) ||   \
    defined(OS_ANDROID) || defined(OS_OPENBSD) || defined(OS_SOLARIS) ||  \
    defined(OS_ANDROID) || defined(OS_NACL) || defined(OS_QNX)
#define OS_POSIX 1
#endif

[xhwang, 2016/12/16 22:37:06]

Does it make sense to have an official USE_ZYGOTE macro/buildflag somewhere?

[Greg K, 2017/01/09 21:45:15]

We may want to define that flag but you probably don't want to do that as part
of this CL. If it breaks anything it'll double the troubleshooting.

[xhwang, 2017/01/12 20:15:02]

okay, then I'll keep this as is.

+    !defined(OS_ANDROID)
+#define POSIX_WITH_ZYGOTE 1
+#endif
+
+namespace base {
+class FilePath;
+}
+
+namespace content {
+
+// Manages all CDM host files.
+class CdmHostFiles {
+ public:
+  CdmHostFiles();
+  ~CdmHostFiles();
+
+#if defined(POSIX_WITH_ZYGOTE)
+  static void CreateGlobalInstance();
+  static std::unique_ptr<CdmHostFiles> TakeGlobalInstance();
+#endif
+
+  static std::unique_ptr<CdmHostFiles> Create(
+      const base::FilePath& cdm_adapter_path);
+
+  // Verifies |cdm_adapter_path| CDM files by calling VerifyCdmFiles() on the
+  // CDM |library|. If unexpected error happens, all files will be closed.

[Greg K, 2017/01/09 21:45:15]

What do you mean by "calling VerifyCdmFiles() on the CDM |library|"?

[xhwang, 2017/01/12 20:15:02]

oops, it should be "calling VerifyHostFiles() exported by the CDM |library|".
Does this answer your question?

[xhwang, 2017/01/18 06:03:59]

Done.

+  // Otherwise, the PlatformFiles are passed to the CDM which will close the
+  // files later.
+  void VerifyFiles(base::NativeLibrary library,
+                   const base::FilePath& cdm_adapter_path);
+
+ private:
+#if defined(POSIX_WITH_ZYGOTE)
+  // Opens all common files and CDM specific files for all registered CDMs.
+  bool OpenFilesForAllRegisteredCdms();
+#endif
+
+  // Opens all common files and CDM specific files for the CDM adapter
+  // registered at |cdm_adapter_path|.
+  bool OpenFiles(const base::FilePath& cdm_adapter_path);
+
+  // Open common CDM host files shared by all CDMs. Upon failure, close all
+  // files opened.
+  bool OpenCommonFiles();
+  // Opens CDM specific files for the CDM adapter registered at

[Haoming Chen, 2017/01/04 22:23:39]

newline

[xhwang, 2017/01/12 20:15:02]

Will do.

[xhwang, 2017/01/18 06:03:59]

Done.

+  // |cdm_adapter_path|. Returns whether all CDM specific files are opened.
+  // Upon failure, close all files opened.
+  bool OpenCdmFiles(const base::FilePath& cdm_adapter_path);
+
+  // Fills |cdm_host_files| with common and CDM specific files for
+  // |cdm_adapter_path|. The ownership of those files are also transferred.
+  // Returns true upon success where the remaining files will be closed.
+  // Returns false upon any failure and all files will be closed.
+  bool TakePlatformFiles(const base::FilePath& cdm_adapter_path,
+                         std::vector<cdm::CdmHostFile>* cdm_host_files);
+
+  void CloseAllFiles();
+
+  using ScopedFileVector = std::vector<std::unique_ptr<CdmHostFile>>;
+  ScopedFileVector common_files_;
+  std::map<base::FilePath, ScopedFileVector> cdm_specific_files_map_;
+};
+
+bool IsCdm(const base::FilePath& cdm_adapter_path);

[Haoming Chen, 2017/01/04 22:23:38]

Add some comments on this function.

[xhwang, 2017/01/12 20:15:02]

Will do.

[xhwang, 2017/01/18 06:03:59]

Done.

+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_MEDIA_CDM_HOST_FILES_H_