1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy 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,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define LOG_TAG "NAsset"
18#include <utils/Log.h>
19
20#include <android/asset_manager_jni.h>
21#include <androidfw/Asset.h>
22#include <androidfw/AssetDir.h>
23#include <androidfw/AssetManager.h>
24#include <utils/threads.h>
25
26#include "jni.h"
27#include "JNIHelp.h"
28
29using namespace android;
30
31// -------------------- Backing implementation of the public API --------------------
32
33// AAssetManager is actually a secret typedef for an empty base class of AssetManager,
34// but AAssetDir and AAsset are actual wrappers for isolation.
35
36// -----
37struct AAssetDir {
38    AssetDir* mAssetDir;
39    size_t mCurFileIndex;
40    String8 mCachedFileName;
41
42    AAssetDir(AssetDir* dir) : mAssetDir(dir), mCurFileIndex(0) { }
43    ~AAssetDir() { delete mAssetDir; }
44};
45
46
47// -----
48struct AAsset {
49    Asset* mAsset;
50
51    AAsset(Asset* asset) : mAsset(asset) { }
52    ~AAsset() { delete mAsset; }
53};
54
55// -------------------- Public native C API --------------------
56
57/**
58 * Supporting information
59 */
60
61static struct assetmanager_offsets_t
62{
63    jfieldID mObject;
64} gAssetManagerOffsets;
65
66static volatile bool gJNIConfigured = false;
67static Mutex gMutex;
68
69/**
70 * Asset Manager functionality
71 */
72AAssetManager* AAssetManager_fromJava(JNIEnv* env, jobject assetManager)
73{
74    {
75        Mutex::Autolock _l(gMutex);
76
77        if (gJNIConfigured == false) {
78            jclass amClass = env->FindClass("android/content/res/AssetManager");
79            gAssetManagerOffsets.mObject = env->GetFieldID(amClass, "mObject", "J");
80            gJNIConfigured = true;
81        }
82    }
83
84    return (AAssetManager*) env->GetLongField(assetManager, gAssetManagerOffsets.mObject);
85}
86
87AAsset* AAssetManager_open(AAssetManager* amgr, const char* filename, int mode)
88{
89    Asset::AccessMode amMode;
90    switch (mode) {
91    case AASSET_MODE_UNKNOWN:
92        amMode = Asset::ACCESS_UNKNOWN;
93        break;
94    case AASSET_MODE_RANDOM:
95        amMode = Asset::ACCESS_RANDOM;
96        break;
97    case AASSET_MODE_STREAMING:
98        amMode = Asset::ACCESS_STREAMING;
99        break;
100    case AASSET_MODE_BUFFER:
101        amMode = Asset::ACCESS_BUFFER;
102        break;
103    default:
104        return NULL;
105    }
106
107    AssetManager* mgr = static_cast<AssetManager*>(amgr);
108    Asset* asset = mgr->open(filename, amMode);
109    if (asset == NULL) {
110        return NULL;
111    }
112
113    return new AAsset(asset);
114}
115
116AAssetDir* AAssetManager_openDir(AAssetManager* amgr, const char* dirName)
117{
118    AssetManager* mgr = static_cast<AssetManager*>(amgr);
119    return new AAssetDir(mgr->openDir(dirName));
120}
121
122/**
123 * AssetDir functionality
124 */
125
126const char* AAssetDir_getNextFileName(AAssetDir* assetDir)
127{
128    const char* returnName = NULL;
129    size_t index = assetDir->mCurFileIndex;
130    const size_t max = assetDir->mAssetDir->getFileCount();
131
132    // Find the next regular file; explicitly don't report directories even if the
133    // underlying implementation changes to report them.  At that point we can add
134    // a more general iterator to this native interface set if appropriate.
135    while ((index < max) && (assetDir->mAssetDir->getFileType(index) != kFileTypeRegular)) {
136        index++;
137    }
138
139    // still in bounds? then the one at 'index' is the next to be reported; generate
140    // the string to return and advance the iterator for next time.
141    if (index < max) {
142        assetDir->mCachedFileName = assetDir->mAssetDir->getFileName(index);
143        returnName = assetDir->mCachedFileName.string();
144        index++;
145    }
146
147    assetDir->mCurFileIndex = index;
148    return returnName;
149}
150
151void AAssetDir_rewind(AAssetDir* assetDir)
152{
153    assetDir->mCurFileIndex = 0;
154}
155
156const char* AAssetDir_getFileName(AAssetDir* assetDir, int index)
157{
158    assetDir->mCachedFileName = assetDir->mAssetDir->getFileName(index);
159    return assetDir->mCachedFileName.string();
160}
161
162void AAssetDir_close(AAssetDir* assetDir)
163{
164    delete assetDir;
165}
166
167/**
168 * Asset functionality
169 */
170
171int AAsset_read(AAsset* asset, void* buf, size_t count)
172{
173    return asset->mAsset->read(buf, (size_t)count);
174}
175
176off_t AAsset_seek(AAsset* asset, off_t offset, int whence)
177{
178    return asset->mAsset->seek(offset, whence);
179}
180
181off64_t AAsset_seek64(AAsset* asset, off64_t offset, int whence)
182{
183    return asset->mAsset->seek(offset, whence);
184}
185
186void AAsset_close(AAsset* asset)
187{
188    asset->mAsset->close();
189    delete asset;
190}
191
192const void* AAsset_getBuffer(AAsset* asset)
193{
194    return asset->mAsset->getBuffer(false);
195}
196
197off_t AAsset_getLength(AAsset* asset)
198{
199    return asset->mAsset->getLength();
200}
201
202off64_t AAsset_getLength64(AAsset* asset)
203{
204    return asset->mAsset->getLength();
205}
206
207off_t AAsset_getRemainingLength(AAsset* asset)
208{
209    return asset->mAsset->getRemainingLength();
210}
211
212off64_t AAsset_getRemainingLength64(AAsset* asset)
213{
214    return asset->mAsset->getRemainingLength();
215}
216
217int AAsset_openFileDescriptor(AAsset* asset, off_t* outStart, off_t* outLength)
218{
219    off64_t outStart64, outLength64;
220
221    int ret = asset->mAsset->openFileDescriptor(&outStart64, &outLength64);
222
223    *outStart = off_t(outStart64);
224    *outLength = off_t(outLength64);
225    return ret;
226}
227
228int AAsset_openFileDescriptor64(AAsset* asset, off64_t* outStart, off64_t* outLength)
229{
230    return asset->mAsset->openFileDescriptor(outStart, outLength);
231}
232
233int AAsset_isAllocated(AAsset* asset)
234{
235    return asset->mAsset->isAllocated() ? 1 : 0;
236}
237