Support content scheme uri for Chrome on Android

base/android/java/src/org/chromium/base/ContentUriUtils.java

 // 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.
 
 package org.chromium.base;
 
 import android.content.ContentResolver;
 import android.content.Context;
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.ParcelFileDescriptor;
 import android.util.Log;
 
 import java.io.File;
+import java.io.FileNotFoundException;
 
 /**
  * This class provides methods to access content URI schemes.
  */
 public abstract class ContentUriUtils {
     private static final String TAG = "ContentUriUtils";
     private static FileProviderUtil sFileProviderUtil;
 
     /**
      * Provides functionality to translate a file into a content URI for use
      * with a content provider.
      */
     public interface FileProviderUtil {
         /**
-         * Generate a content uri from the given file.
+         * Generate a content URI from the given file.
          * @param context Application context.
          * @param file The file to be translated.
          */
-        public Uri getContentUriFromFile(Context context, File file);
+        Uri getContentUriFromFile(Context context, File file);
     }
 
     // Prevent instantiation.
     private ContentUriUtils() {}
 
     public static void setFileProviderUtil(FileProviderUtil util) {
         sFileProviderUtil = util;
     }
 
     public static Uri getContentUriFromFile(Context context, File file) {
         ThreadUtils.assertOnUiThread();
         if (sFileProviderUtil != null) {
             return sFileProviderUtil.getContentUriFromFile(context, file);
         }
         return null;
     }
 
     /**
      * Opens the content URI for reading, and returns the file descriptor to
      * the caller. The caller is responsible for closing the file desciptor.
      *
      * @param context {@link Context} in interest
      * @param uriString the content URI to open
-     * @returns file desciptor upon sucess, or -1 otherwise.
+     * @return file desciptor upon sucess, or -1 otherwise.
      */
     @CalledByNative
     public static int openContentUriForRead(Context context, String uriString) {
         ParcelFileDescriptor pfd = getParcelFileDescriptor(context, uriString);
         if (pfd != null) {
             return pfd.detachFd();
         }
         return -1;
     }
 
     /**
      * Check whether a content URI exists.
      *
      * @param context {@link Context} in interest.
      * @param uriString the content URI to query.
-     * @returns true if the uri exists, or false otherwise.
+     * @return true if the URI exists, or false otherwise.
      */
     @CalledByNative
     public static boolean contentUriExists(Context context, String uriString) {
-        ParcelFileDescriptor pfd = getParcelFileDescriptor(context, uriString);
-        if (pfd == null) {
-            return false;
-        }
-        return true;
+        return getParcelFileDescriptor(context, uriString) != null;
     }
 
     /**
-     * Helper method to open a content URI and return the ParcelFileDescriptor.
+     * Retrieve the MIME type for the content URI.
+     *
+     * @param context {@link Context} in interest.
+     * @param uriString the content URI to look up.
+     * @return MIME type or null if the input params are empty or invalid.
+     */
+    @CalledByNative
+    public static String getMimeType(Context context, String uriString) {
+        ContentResolver resolver = context.getContentResolver();
+        if (resolver == null) return null;
+        Uri uri = Uri.parse(uriString);
+        return resolver.getType(uri);
+    }
+
+    /**
+     * Helper method to open a content URI and returns the ParcelFileDescriptor.
      *
      * @param context {@link Context} in interest.
      * @param uriString the content URI to open.
-     * @returns ParcelFileDescriptor of the content URI, or NULL if the file does not exist.
+     * @return ParcelFileDescriptor of the content URI, or NULL if the file does not exist.
      */
     private static ParcelFileDescriptor getParcelFileDescriptor(Context context, String uriString) {
         ContentResolver resolver = context.getContentResolver();
         Uri uri = Uri.parse(uriString);
 
         ParcelFileDescriptor pfd = null;
         try {
             pfd = resolver.openFileDescriptor(uri, "r");
-        } catch (java.io.FileNotFoundException e) {
+        } catch (FileNotFoundException e) {
             Log.w(TAG, "Cannot find content uri: " + uriString, e);
+        } catch (SecurityException e) {
+            Log.w(TAG, "Cannot open content uri: " + uriString, e);
+        } catch (IllegalArgumentException e) {
+            Log.w(TAG, "Unknown content uri: " + uriString, e);
         }
         return pfd;
     }
 
     /**
      * Method to resolve the display name of a content URI.
      *
      * @param uri the content URI to be resolved.
      * @param contentResolver the content resolver to query.
      * @param columnField the column field to query.
-     * @returns the display name of the @code uri if present in the database
+     * @return the display name of the @code uri if present in the database
      *  or an empty string otherwise.
      */
     public static String getDisplayName(
             Uri uri, ContentResolver contentResolver, String columnField) {
         if (contentResolver == null || uri == null) return "";
         Cursor cursor = null;
         try {
             cursor = contentResolver.query(uri, null, null, null, null);
 
             if (cursor != null && cursor.getCount() >= 1) {
                 cursor.moveToFirst();
                 int index = cursor.getColumnIndex(columnField);
                 if (index > -1) return cursor.getString(index);
             }
         } catch (NullPointerException e) {
             // Some android models don't handle the provider call correctly.
             // see crbug.com/345393
             return "";
         } finally {
             if (cursor != null) cursor.close();
         }
         return "";
     }
 }