Delete FilesystemInterface::CopyFile.

Only use of this method was to implement the cross-device case of
MoveFile on unix systems.

In turn, only use of the MoveFile method is in
FileRotatingStream::RotateFiles. Since file rotation should never
involve any copying of log data, the MoveFile fallback to copying can
be deleted.

BUG=webrtc:6424

Review-Url: https://codereview.webrtc.org/2747373003
Cr-Commit-Position: refs/heads/master@{#17364}

webrtc/base/fileutils.h

@@ -118,15 +118,8 @@ class FilesystemInterface {
   // This moves a file from old_path to new_path, where "old_path" is a
   // plain file. This DCHECKs and returns false if old_path points to a
   // directory, and returns true if the function succeeds.
-  // If the new path is on a different volume than the old path, this function
-  // will attempt to copy and, if that succeeds, delete the old path.
   virtual bool MoveFile(const Pathname &old_path, const Pathname &new_path) = 0;
 
-  // This copies a file from old_path to new_path. This method DCHECKs and
-  // returns false if old_path is a folder, and returns true if the copy
-  // succeeds.
-  virtual bool CopyFile(const Pathname &old_path, const Pathname &new_path) = 0;
-
   // Returns true if pathname refers to a directory
   virtual bool IsFolder(const Pathname& pathname) = 0;
 
@@ -230,10 +223,6 @@ class Filesystem {
     return EnsureDefaultFilesystem()->MoveFile(old_path, new_path);
   }
 
-  static bool CopyFile(const Pathname &old_path, const Pathname &new_path) {
-    return EnsureDefaultFilesystem()->CopyFile(old_path, new_path);
-  }
-
   static bool IsFolder(const Pathname& pathname) {
     return EnsureDefaultFilesystem()->IsFolder(pathname);
   }

webrtc/base/unixfilesystem.cc

@@ -204,12 +204,7 @@ bool UnixFilesystem::MoveFile(const Pathname &old_path,
   LOG(LS_VERBOSE) << "Moving " << old_path.pathname()
                   << " to " << new_path.pathname();
   if (rename(old_path.pathname().c_str(), new_path.pathname().c_str()) != 0) {
-    if (errno != EXDEV)
-      return false;
-    if (!CopyFile(old_path, new_path))
-      return false;
-    if (!DeleteFile(old_path))
-      return false;
+    return false;
   }
   return true;
 }
@@ -221,31 +216,6 @@ bool UnixFilesystem::IsFolder(const Pathname &path) {
   return S_ISDIR(st.st_mode);
 }
 
-bool UnixFilesystem::CopyFile(const Pathname &old_path,
-                              const Pathname &new_path) {
-  LOG(LS_VERBOSE) << "Copying " << old_path.pathname()
-                  << " to " << new_path.pathname();
-  char buf[256];
-  size_t len;
-
-  StreamInterface *source = OpenFile(old_path, "rb");
-  if (!source)
-    return false;
-
-  StreamInterface *dest = OpenFile(new_path, "wb");
-  if (!dest) {
-    delete source;
-    return false;
-  }
-
-  while (source->Read(buf, sizeof(buf), &len, nullptr) == SR_SUCCESS)
-    dest->Write(buf, len, nullptr, nullptr);
-
-  delete source;
-  delete dest;
-  return true;
-}
-
 bool UnixFilesystem::IsTemporaryPath(const Pathname& pathname) {
 #if defined(WEBRTC_ANDROID) || defined(WEBRTC_MAC)
   RTC_DCHECK(provided_app_temp_folder_ != nullptr);

webrtc/base/unixfilesystem.h

@@ -62,11 +62,6 @@ class UnixFilesystem : public FilesystemInterface {
   // Returns true if function succeeds.
   bool MoveFile(const Pathname& old_path, const Pathname& new_path) override;
 
-  // This copies a file from old_path to _new_path where "file" can be a plain
-  // file or directory, which will be copied recursively.
-  // Returns true if function succeeds
-  bool CopyFile(const Pathname& old_path, const Pathname& new_path) override;
-
   // Returns true if a pathname is a directory
   bool IsFolder(const Pathname& pathname) override;
 

webrtc/base/win32filesystem.cc

@@ -160,12 +160,6 @@ bool Win32Filesystem::IsAbsent(const Pathname& path) {
   return (ERROR_FILE_NOT_FOUND == err || ERROR_PATH_NOT_FOUND == err);
 }
 
-bool Win32Filesystem::CopyFile(const Pathname &old_path,
-                               const Pathname &new_path) {
-  return ::CopyFile(ToUtf16(old_path.pathname()).c_str(),
-                    ToUtf16(new_path.pathname()).c_str(), TRUE) != 0;
-}
-
 bool Win32Filesystem::IsTemporaryPath(const Pathname& pathname) {
   TCHAR buffer[MAX_PATH + 1];
   if (!::GetTempPath(arraysize(buffer), buffer))

webrtc/base/win32filesystem.h

@@ -41,10 +41,6 @@ class Win32Filesystem : public FilesystemInterface {
   // Returns true if the file is successfully moved
   virtual bool MoveFile(const Pathname &old_path, const Pathname &new_path);
   
-  // This copies a file from old_path to _new_path
-  // Returns true if function succeeds
-  virtual bool CopyFile(const Pathname &old_path, const Pathname &new_path);
-
   // Returns true if a pathname is a directory
   virtual bool IsFolder(const Pathname& pathname);