1/*
2 * Copyright (C) 2008 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#include "android_nio_utils.h"
18
19#include "core_jni_helpers.h"
20
21struct NioJNIData {
22    jclass nioAccessClass;
23
24    jmethodID getBasePointerID;
25    jmethodID getBaseArrayID;
26    jmethodID getBaseArrayOffsetID;
27};
28
29static NioJNIData gNioJNI;
30
31void* android::nio_getPointer(JNIEnv *_env, jobject buffer, jarray *array) {
32    assert(array);
33
34    jlong pointer;
35    jint offset;
36    void *data;
37
38    pointer = _env->CallStaticLongMethod(gNioJNI.nioAccessClass,
39                                         gNioJNI.getBasePointerID, buffer);
40    if (pointer != 0L) {
41        *array = NULL;
42        return reinterpret_cast<void *>(pointer);
43    }
44
45    *array = (jarray) _env->CallStaticObjectMethod(gNioJNI.nioAccessClass,
46                                               gNioJNI.getBaseArrayID, buffer);
47    offset = _env->CallStaticIntMethod(gNioJNI.nioAccessClass,
48                                       gNioJNI.getBaseArrayOffsetID, buffer);
49    data = _env->GetPrimitiveArrayCritical(*array, (jboolean *) 0);
50
51    return (void *) ((char *) data + offset);
52}
53
54
55void android::nio_releasePointer(JNIEnv *_env, jarray array, void *data,
56                                jboolean commit) {
57    _env->ReleasePrimitiveArrayCritical(array, data,
58                                        commit ? 0 : JNI_ABORT);
59}
60
61///////////////////////////////////////////////////////////////////////////////
62
63android::AutoBufferPointer::AutoBufferPointer(JNIEnv* env, jobject nioBuffer,
64                                              jboolean commit) {
65    fEnv = env;
66    fCommit = commit;
67    fPointer = android::nio_getPointer(env, nioBuffer, &fArray);
68}
69
70android::AutoBufferPointer::~AutoBufferPointer() {
71    if (NULL != fArray) {
72        android::nio_releasePointer(fEnv, fArray, fPointer, fCommit);
73    }
74}
75
76///////////////////////////////////////////////////////////////////////////////
77
78namespace android {
79
80int register_android_nio_utils(JNIEnv* env) {
81    jclass localClass = FindClassOrDie(env, "java/nio/NIOAccess");
82    gNioJNI.getBasePointerID = GetStaticMethodIDOrDie(env, localClass, "getBasePointer",
83                                                      "(Ljava/nio/Buffer;)J");
84    gNioJNI.getBaseArrayID = GetStaticMethodIDOrDie(env, localClass, "getBaseArray",
85                                                    "(Ljava/nio/Buffer;)Ljava/lang/Object;");
86    gNioJNI.getBaseArrayOffsetID = GetStaticMethodIDOrDie(env, localClass, "getBaseArrayOffset",
87                                                          "(Ljava/nio/Buffer;)I");
88
89    // now record a permanent version of the class ID
90    gNioJNI.nioAccessClass = MakeGlobalRefOrDie(env, localClass);
91
92    return 0;
93}
94
95}
96