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 public static final int BASE_URI_LEN = BASE_URI.length(); 42 43 @Override 44 public String getType(Uri uri) { 45 // If the mimetype is not appended to the uri, then return an empty string 46 String mimetype = uri.getQuery(); 47 return mimetype == null ? "" : mimetype; 48 } 49 50 @Override 51 public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException { 52 // android:exported="false" is broken in older releases so we have to 53 // manually enforce the calling identity. 54 if (Process.myUid() != Binder.getCallingUid()) { 55 throw new SecurityException("Permission denied"); 56 } 57 if (!"r".equals(mode)) { 58 throw new FileNotFoundException("Bad mode for " + uri + ": " + mode); 59 } 60 String filename = uri.toString().substring(BASE_URI_LEN); 61 return ParcelFileDescriptor.open(new File(filename), 62 ParcelFileDescriptor.MODE_READ_ONLY); 63 } 64 65 @Override 66 public int delete(Uri uri, String selection, String[] selectionArgs) { 67 throw new UnsupportedOperationException(); 68 } 69 70 @Override 71 public Uri insert(Uri uri, ContentValues values) { 72 throw new UnsupportedOperationException(); 73 } 74 75 @Override 76 public boolean onCreate() { 77 return true; 78 } 79 80 @Override 81 public Cursor query(Uri uri, String[] projection, String selection, 82 String[] selectionArgs, String sortOrder) { 83 throw new UnsupportedOperationException(); 84 } 85 86 @Override 87 public int update(Uri uri, ContentValues values, String selection, 88 String[] selectionArgs) { 89 throw new UnsupportedOperationException(); 90 } 91 92 } 93
