Sniff MIME type for files which have unknown extensions.

apps/launcher.cc

 // Copyright 2013 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 "apps/launcher.h"
 
 #include "apps/browser/api/app_runtime/app_runtime_api.h"
 #include "apps/browser/file_handler_util.h"
 #include "apps/common/api/app_runtime.h"
 #include "base/command_line.h"
@@ skipping 11 matching lines @@
 #include "content/public/browser/web_contents.h"
 #include "extensions/browser/event_router.h"
 #include "extensions/browser/extension_host.h"
 #include "extensions/browser/extension_prefs.h"
 #include "extensions/browser/extension_system.h"
 #include "extensions/browser/lazy_background_task_queue.h"
 #include "extensions/browser/process_manager.h"
 #include "extensions/common/extension.h"
 #include "extensions/common/extension_messages.h"
 #include "extensions/common/manifest_handlers/kiosk_mode_info.h"
+#include "net/base/filename_util.h"
+#include "net/base/mime_sniffer.h"
 #include "net/base/mime_util.h"
 #include "net/base/net_util.h"
 #include "url/gurl.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/chromeos/drive/file_errors.h"
 #include "chrome/browser/chromeos/drive/file_system_interface.h"
 #include "chrome/browser/chromeos/drive/file_system_util.h"
 #include "chrome/browser/chromeos/login/user_manager.h"
 #endif
@@ skipping 132 matching lines @@
     // If the file doesn't exist, or is a directory, launch with no launch data.
     if (!base::PathExists(file_path_) ||
         base::DirectoryExists(file_path_)) {
       LOG(WARNING) << "No file exists with path " << file_path_.value();
       BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, base::Bind(
               &PlatformAppPathLauncher::LaunchWithNoLaunchData, this));
       return;
     }
 
     std::string mime_type;
-    if (!net::GetMimeTypeFromFile(file_path_, &mime_type))
-      mime_type = kFallbackMimeType;
+    if (!net::GetMimeTypeFromFile(file_path_, &mime_type)) {
+      // If MIME type can't be determined by the file path,
+      // Try to sniff by its content.
+      std::vector<char> content(net::kMaxBytesToSniff);
+      int bytes_read = base::ReadFile(file_path_, &content[0], content.size());
+      if (bytes_read >= 0) {
+        net::SniffMimeType(&content[0],
+                           bytes_read,
+                           net::FilePathToFileURL(file_path_),
+                           std::string(),

[hashimoto, 2014/04/10 09:29:12]

nit: How about adding a comment like "// type_hit" to tell future readers what
this string is?

[fukino, 2014/04/10 11:12:06]

Done.

+                           &mime_type);
+      }
+      if (mime_type.empty())
+        mime_type = kFallbackMimeType;
+    }
 
     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, base::Bind(
             &PlatformAppPathLauncher::LaunchWithMimeType, this, mime_type));
   }
 
 #if defined(OS_CHROMEOS)
   void GetMimeTypeAndLaunchForDriveFile() {
     DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
     drive::FileSystemInterface* file_system =
@@ skipping 194 matching lines @@
 void LaunchPlatformAppWithUrl(Profile* profile,
                               const Extension* extension,
                               const std::string& handler_id,
                               const GURL& url,
                               const GURL& referrer_url) {
   AppEventRouter::DispatchOnLaunchedEventWithUrl(
       profile, extension, handler_id, url, referrer_url);
 }
 
 }  // namespace apps