Make base:ReplaceFile return an informative error.

base/platform_file_posix.cc

 // Copyright (c) 2012 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.
 
 #include "base/platform_file.h"
 
 #include <fcntl.h>
 #include <errno.h>
 #include <sys/stat.h>
 #include <unistd.h>
@@ skipping 104 matching lines @@
       (flags & (PLATFORM_FILE_CREATE_ALWAYS | PLATFORM_FILE_CREATE)))
     *created = true;
 
   if ((descriptor >= 0) && (flags & PLATFORM_FILE_DELETE_ON_CLOSE)) {
     unlink(name.value().c_str());
   }
 
   if (error) {
     if (descriptor >= 0)
       *error = PLATFORM_FILE_OK;
-    else {
-      switch (errno) {
-        case EACCES:
-        case EISDIR:
-        case EROFS:
-        case EPERM:
-          *error = PLATFORM_FILE_ERROR_ACCESS_DENIED;
-          break;
-        case ETXTBSY:
-          *error = PLATFORM_FILE_ERROR_IN_USE;
-          break;
-        case EEXIST:
-          *error = PLATFORM_FILE_ERROR_EXISTS;
-          break;
-        case ENOENT:
-          *error = PLATFORM_FILE_ERROR_NOT_FOUND;
-          break;
-        case EMFILE:
-          *error = PLATFORM_FILE_ERROR_TOO_MANY_OPENED;
-          break;
-        case ENOMEM:
-          *error = PLATFORM_FILE_ERROR_NO_MEMORY;
-          break;
-        case ENOSPC:
-          *error = PLATFORM_FILE_ERROR_NO_SPACE;
-          break;
-        case ENOTDIR:
-          *error = PLATFORM_FILE_ERROR_NOT_A_DIRECTORY;
-          break;
-        default:
-          *error = PLATFORM_FILE_ERROR_FAILED;
-      }
-    }
+    else
+      *error = ErrnoToPlatformFileError(errno);
   }
 
   return descriptor;
 }
 
 FILE* FdopenPlatformFile(PlatformFile file, const char* mode) {
   return fdopen(file, mode);
 }
 
 bool ClosePlatformFile(PlatformFile file) {
@@ skipping 160 matching lines @@
 
   info->is_directory = S_ISDIR(file_info.st_mode);
   info->is_symbolic_link = S_ISLNK(file_info.st_mode);
   info->size = file_info.st_size;
   info->last_modified = base::Time::FromTimeT(file_info.st_mtime);
   info->last_accessed = base::Time::FromTimeT(file_info.st_atime);
   info->creation_time = base::Time::FromTimeT(file_info.st_ctime);
   return true;
 }
 
+PlatformFileError ErrnoToPlatformFileError(int saved_errno) {
+  switch (saved_errno) {
+    case EACCES:
+    case EISDIR:
+    case EROFS:
+    case EPERM:
+      return PLATFORM_FILE_ERROR_ACCESS_DENIED;
+    case ETXTBSY:
+      return PLATFORM_FILE_ERROR_IN_USE;
+    case EEXIST:
+      return PLATFORM_FILE_ERROR_EXISTS;
+    case ENOENT:
+      return PLATFORM_FILE_ERROR_NOT_FOUND;
+    case EMFILE:
+      return PLATFORM_FILE_ERROR_TOO_MANY_OPENED;
+    case ENOMEM:
+      return PLATFORM_FILE_ERROR_NO_MEMORY;
+    case ENOSPC:
+      return PLATFORM_FILE_ERROR_NO_SPACE;
+    case ENOTDIR:
+      return PLATFORM_FILE_ERROR_NOT_A_DIRECTORY;
+    default:
+      return PLATFORM_FILE_ERROR_FAILED;
+  }
+}
+
 }  // namespace base