1 /** 2 * Copyright (C) 2008 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not 5 * use this file except in compliance with the License. You may obtain a copy 6 * of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 13 * License for the specific language governing permissions and limitations 14 * under the License. 15 */ 16 17 package com.android.htmlviewer; 18 19 import java.io.FileNotFoundException; 20 import java.io.File; 21 import java.lang.UnsupportedOperationException; 22 23 import android.content.ContentProvider; 24 import android.content.ContentValues; 25 import android.database.Cursor; 26 import android.net.Uri; 27 import android.os.Binder; 28 import android.os.ParcelFileDescriptor; 29 import android.os.Process; 30 31 /** 32 * WebView does not support file: loading. This class wraps a file load 33 * with a content provider. 34 * As HTMLViewer does not have internet access nor does it allow 35 * Javascript to be run, it is safe to load file based HTML content. 36 */ 37 public class FileContentProvider extends ContentProvider { 38 39 public static final String BASE_URI = 40 "content://com.android.htmlfileprovider"; 41 42 @Override getType(Uri uri)43 public String getType(Uri uri) { 44 // If the mimetype is not appended to the uri, then return an empty string 45 String mimetype = uri.getQuery(); 46 return mimetype == null ? "" : mimetype; 47 } 48 49 @Override openFile(Uri uri, String mode)50 public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException { 51 // android:exported="false" is broken in older releases so we have to 52 // manually enforce the calling identity. 53 if (Process.myUid() != Binder.getCallingUid()) { 54 throw new SecurityException("Permission denied"); 55 } 56 if (!"r".equals(mode)) { 57 throw new FileNotFoundException("Bad mode for " + uri + ": " + mode); 58 } 59 String filename = uri.getPath(); 60 return ParcelFileDescriptor.open(new File(filename), 61 ParcelFileDescriptor.MODE_READ_ONLY); 62 } 63 64 @Override delete(Uri uri, String selection, String[] selectionArgs)65 public int delete(Uri uri, String selection, String[] selectionArgs) { 66 throw new UnsupportedOperationException(); 67 } 68 69 @Override insert(Uri uri, ContentValues values)70 public Uri insert(Uri uri, ContentValues values) { 71 throw new UnsupportedOperationException(); 72 } 73 74 @Override onCreate()75 public boolean onCreate() { 76 return true; 77 } 78 79 @Override query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder)80 public Cursor query(Uri uri, String[] projection, String selection, 81 String[] selectionArgs, String sortOrder) { 82 throw new UnsupportedOperationException(); 83 } 84 85 @Override update(Uri uri, ContentValues values, String selection, String[] selectionArgs)86 public int update(Uri uri, ContentValues values, String selection, 87 String[] selectionArgs) { 88 throw new UnsupportedOperationException(); 89 } 90 91 } 92