From ada218c0897f12ccaff39dabd87bcb04214f0ae5 Mon Sep 17 00:00:00 2001
From: Thomas Inskip <tinskip@google.com>
Date: Wed, 20 May 2015 10:14:36 -0700
Subject: [PATCH] Added File Seek and Tell functionality. Added ability to open
 files in direct-access mode (no buffering).

Change-Id: Icca71a60f6697967e7535a030c71414de95d8044
---
 packager/media/file/file.cc             | 40 ++++++++++++++++++-------
 packager/media/file/file.h              | 21 +++++++++++++
 packager/media/file/local_file.cc       | 14 +++++++++
 packager/media/file/local_file.h        |  2 ++
 packager/media/file/threaded_io_file.cc | 10 +++++++
 packager/media/file/threaded_io_file.h  |  2 ++
 packager/media/file/udp_file.h          |  2 ++
 packager/media/file/udp_file_posix.cc   | 10 +++++++
 packager/media/file/udp_file_win.cc     | 10 +++++++
 9 files changed, 100 insertions(+), 11 deletions(-)

diff --git a/packager/media/file/file.cc b/packager/media/file/file.cc
index cab663244d..d61f1e4a3c 100644
--- a/packager/media/file/file.cc
+++ b/packager/media/file/file.cc
@@ -74,17 +74,8 @@ static const SupportedTypeInfo kSupportedTypeInfo[] = {
 }  // namespace
 
 File* File::Create(const char* file_name, const char* mode) {
-  scoped_ptr<File, FileCloser> internal_file;
-  for (size_t i = 0; i < arraysize(kSupportedTypeInfo); ++i) {
-    const SupportedTypeInfo& type_info = kSupportedTypeInfo[i];
-    if (strncmp(type_info.type, file_name, type_info.type_length) == 0) {
-      internal_file.reset(type_info.factory_function(
-          file_name + type_info.type_length, mode));
-    }
-  }
-  // Otherwise we assume it is a local file
-  if (!internal_file)
-    internal_file.reset(CreateLocalFile(file_name, mode));
+  scoped_ptr<File, FileCloser> internal_file(
+      CreateInternalFile(file_name, mode));
 
   if (FLAGS_io_cache_size) {
     // Enable threaded I/O for "r", "w", and "a" modes only.
@@ -106,6 +97,22 @@ File* File::Create(const char* file_name, const char* mode) {
   return internal_file.release();
 }
 
+File* File::CreateInternalFile(const char* file_name, const char* mode) {
+  scoped_ptr<File, FileCloser> internal_file;
+  for (size_t i = 0; i < arraysize(kSupportedTypeInfo); ++i) {
+    const SupportedTypeInfo& type_info = kSupportedTypeInfo[i];
+    if (strncmp(type_info.type, file_name, type_info.type_length) == 0) {
+      internal_file.reset(type_info.factory_function(
+          file_name + type_info.type_length, mode));
+    }
+  }
+  // Otherwise we assume it is a local file
+  if (!internal_file)
+    internal_file.reset(CreateLocalFile(file_name, mode));
+
+  return internal_file.release();
+}
+
 File* File::Open(const char* file_name, const char* mode) {
   File* file = File::Create(file_name, mode);
   if (!file)
@@ -117,6 +124,17 @@ File* File::Open(const char* file_name, const char* mode) {
   return file;
 }
 
+File* File::OpenWithNoBuffering(const char* file_name, const char* mode) {
+  File* file = File::CreateInternalFile(file_name, mode);
+  if (!file)
+    return NULL;
+  if (!file->Open()) {
+    delete file;
+    return NULL;
+  }
+  return file;
+}
+
 bool File::Delete(const char* file_name) {
   for (size_t i = 0; i < arraysize(kSupportedTypeInfo); ++i) {
     const SupportedTypeInfo& type_info = kSupportedTypeInfo[i];
diff --git a/packager/media/file/file.h b/packager/media/file/file.h
index 01bfe05f8d..7d58f624ec 100644
--- a/packager/media/file/file.h
+++ b/packager/media/file/file.h
@@ -29,6 +29,14 @@ class File {
   /// @return A File pointer on success, false otherwise.
   static File* Open(const char* file_name, const char* mode);
 
+  /// Open the specified file in direct-access mode (no buffering).
+  /// This is a file factory method, it opens a proper file automatically
+  /// based on prefix, e.g. "file://" for LocalFile.
+  /// @param file_name contains the name of the file to be accessed.
+  /// @param mode contains file access mode. Implementation dependent.
+  /// @return A File pointer on success, false otherwise.
+  static File* OpenWithNoBuffering(const char* file_name, const char* mode);
+
   /// Delete the specified file.
   /// @param file_name contains the path of the file to be deleted.
   /// @return true if successful, false otherwise.
@@ -66,6 +74,17 @@ class File {
   /// @return true on success, false otherwise.
   virtual bool Flush() = 0;
 
+  /// Seek to the specifield position in the file.
+  /// @param position is the position to seek to.
+  /// @return true on success, false otherwise.
+  virtual bool Seek(uint64_t position) = 0;
+
+  /// Get the current file position.
+  /// @param position is a pointer to contain the current file position upon
+  ///        successful return.
+  /// @return true on succcess, false otherwise.
+  virtual bool Tell(uint64_t* position) = 0;
+
   /// @return The file name.
   const std::string& file_name() const { return file_name_; }
 
@@ -99,6 +118,8 @@ class File {
   // LocalFile, MemFile based on prefix.
   static File* Create(const char* file_name, const char* mode);
 
+  static File* CreateInternalFile(const char* file_name, const char* mode);
+
   std::string file_name_;
   DISALLOW_COPY_AND_ASSIGN(File);
 };
diff --git a/packager/media/file/local_file.cc b/packager/media/file/local_file.cc
index 35a1d11082..bba5168222 100644
--- a/packager/media/file/local_file.cc
+++ b/packager/media/file/local_file.cc
@@ -6,6 +6,8 @@
 
 #include "packager/media/file/local_file.h"
 
+#include <stdio.h>
+
 #include "packager/base/file_util.h"
 #include "packager/base/logging.h"
 
@@ -59,6 +61,18 @@ bool LocalFile::Flush() {
   return ((fflush(internal_file_) == 0) && !ferror(internal_file_));
 }
 
+bool LocalFile::Seek(uint64_t position) {
+  return fseeko(internal_file_, position, SEEK_SET) >= 0;
+}
+
+bool LocalFile::Tell(uint64_t* position) {
+  off_t offset = ftello(internal_file_);
+  if (offset < 0)
+    return false;
+  *position = offset;
+  return true;
+}
+
 LocalFile::~LocalFile() {}
 
 bool LocalFile::Open() {
diff --git a/packager/media/file/local_file.h b/packager/media/file/local_file.h
index 18bb38ac67..aacaa94df0 100644
--- a/packager/media/file/local_file.h
+++ b/packager/media/file/local_file.h
@@ -32,6 +32,8 @@ class LocalFile : public File {
   virtual int64_t Write(const void* buffer, uint64_t length) OVERRIDE;
   virtual int64_t Size() OVERRIDE;
   virtual bool Flush() OVERRIDE;
+  virtual bool Seek(uint64_t position) OVERRIDE;
+  virtual bool Tell(uint64_t* position) OVERRIDE;
   /// @}
 
   /// Delete a local file.
diff --git a/packager/media/file/threaded_io_file.cc b/packager/media/file/threaded_io_file.cc
index e2dca86ec5..b58c1f7ff0 100644
--- a/packager/media/file/threaded_io_file.cc
+++ b/packager/media/file/threaded_io_file.cc
@@ -123,6 +123,16 @@ void ThreadedIoFile::RunInInputMode() {
   }
 }
 
+bool ThreadedIoFile::Seek(uint64_t position) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
+bool ThreadedIoFile::Tell(uint64_t* position) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
 void ThreadedIoFile::RunInOutputMode() {
   DCHECK(internal_file_);
   DCHECK(thread_);
diff --git a/packager/media/file/threaded_io_file.h b/packager/media/file/threaded_io_file.h
index 0f5be3285e..ba3611562a 100644
--- a/packager/media/file/threaded_io_file.h
+++ b/packager/media/file/threaded_io_file.h
@@ -38,6 +38,8 @@ class ThreadedIoFile : public File {
   virtual int64_t Write(const void* buffer, uint64_t length) OVERRIDE;
   virtual int64_t Size() OVERRIDE;
   virtual bool Flush() OVERRIDE;
+  virtual bool Seek(uint64_t position) OVERRIDE;
+  virtual bool Tell(uint64_t* position) OVERRIDE;
   /// @}
 
  protected:
diff --git a/packager/media/file/udp_file.h b/packager/media/file/udp_file.h
index 415c00ee7c..ef64f4a140 100644
--- a/packager/media/file/udp_file.h
+++ b/packager/media/file/udp_file.h
@@ -31,6 +31,8 @@ class UdpFile : public File {
   virtual int64_t Write(const void* buffer, uint64_t length) OVERRIDE;
   virtual int64_t Size() OVERRIDE;
   virtual bool Flush() OVERRIDE;
+  virtual bool Seek(uint64_t position) OVERRIDE;
+  virtual bool Tell(uint64_t* position) OVERRIDE;
   /// @}
 
  protected:
diff --git a/packager/media/file/udp_file_posix.cc b/packager/media/file/udp_file_posix.cc
index c376c4fc96..6df6fbf368 100644
--- a/packager/media/file/udp_file_posix.cc
+++ b/packager/media/file/udp_file_posix.cc
@@ -129,6 +129,16 @@ bool UdpFile::Flush() {
   return false;
 }
 
+bool UdpFile::Seek(uint64_t position) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
+bool UdpFile::Tell(uint64_t* position) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
 class ScopedSocket {
  public:
   explicit ScopedSocket(int sock_fd)
diff --git a/packager/media/file/udp_file_win.cc b/packager/media/file/udp_file_win.cc
index 49a48beec6..38c94b2e75 100644
--- a/packager/media/file/udp_file_win.cc
+++ b/packager/media/file/udp_file_win.cc
@@ -42,6 +42,16 @@ bool UdpFile::Flush() {
   return false;
 }
 
+bool UdpFile::Seek(uint64_t position) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
+bool UdpFile::Tell(uint64_t* position) {
+  NOTIMPLEMENTED();
+  return false;
+}
+
 bool UdpFile::Open() {
   NOTIMPLEMENTED();
   return false;