JniInternal.h revision e2557513420f6be2d70c19a4d826731174c828d1 
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 * JNI innards, common to the regular and "checked" interfaces.
18 */
19#ifndef _DALVIK_JNIINTERNAL
20#define _DALVIK_JNIINTERNAL
21
22#include "jni.h"
23
24/* system init/shutdown */
25bool dvmJniStartup(void);
26void dvmJniShutdown(void);
27
28/*
29 * Our data structures for JNIEnv and JavaVM.
30 *
31 * Native code thinks it has a pointer to a pointer.  We know better.
32 */
33struct JavaVMExt;
34
35typedef struct JNIEnvExt {
36    const struct JNINativeInterface* funcTable;     /* must be first */
37
38    const struct JNINativeInterface* baseFuncTable;
39
40    /* pointer to the VM we are a part of */
41    struct JavaVMExt* vm;
42
43    u4      envThreadId;
44    Thread* self;
45
46    /* if nonzero, we are in a "critical" JNI call */
47    int     critical;
48
49    /* keep a copy of this here for speed */
50    bool    forceDataCopy;
51
52    struct JNIEnvExt* prev;
53    struct JNIEnvExt* next;
54} JNIEnvExt;
55
56typedef struct JavaVMExt {
57    const struct JNIInvokeInterface* funcTable;     /* must be first */
58
59    const struct JNIInvokeInterface* baseFuncTable;
60
61    /* if multiple VMs are desired, add doubly-linked list stuff here */
62
63    /* per-VM feature flags */
64    bool    useChecked;
65    bool    warnError;
66    bool    forceDataCopy;
67
68    /* head of list of JNIEnvs associated with this VM */
69    JNIEnvExt*      envList;
70    pthread_mutex_t envListLock;
71} JavaVMExt;
72
73/*
74 * Native function return type; used by dvmPlatformInvoke().
75 *
76 * This is part of Method.jniArgInfo, and must fit in 3 bits.
77 * Note: Assembly code in arch/<arch>/Call<arch>.S relies on
78 * the enum values defined here.
79 */
80typedef enum DalvikJniReturnType {
81    DALVIK_JNI_RETURN_VOID = 0,     /* must be zero */
82    DALVIK_JNI_RETURN_FLOAT = 1,
83    DALVIK_JNI_RETURN_DOUBLE = 2,
84    DALVIK_JNI_RETURN_S8 = 3,
85    DALVIK_JNI_RETURN_S4 = 4,
86    DALVIK_JNI_RETURN_S2 = 5,
87    DALVIK_JNI_RETURN_U2 = 6,
88    DALVIK_JNI_RETURN_S1 = 7
89} DalvikJniReturnType;
90
91#define DALVIK_JNI_NO_ARG_INFO  0x80000000
92#define DALVIK_JNI_RETURN_MASK  0x70000000
93#define DALVIK_JNI_RETURN_SHIFT 28
94#define DALVIK_JNI_COUNT_MASK   0x0f000000
95#define DALVIK_JNI_COUNT_SHIFT  24
96
97
98/*
99 * Pop the JNI local stack when we return from a native method.  "saveArea"
100 * points to the StackSaveArea for the method we're leaving.
101 */
102INLINE void dvmPopJniLocals(Thread* self, StackSaveArea* saveArea)
103{
104    if (saveArea->xtra.localRefTop != self->jniLocalRefTable.nextEntry) {
105        LOGVV("LREF: popped %d entries (%d remain)\n",
106            (int)(self->jniLocalRefTable.nextEntry-saveArea->xtra.localRefTop),
107            (int)(saveArea->xtra.localRefTop - self->jniLocalRefTable.table));
108    }
109    self->jniLocalRefTable.nextEntry = saveArea->xtra.localRefTop;
110}
111
112/*
113 * Set the envThreadId field.
114 */
115INLINE void dvmSetJniEnvThreadId(JNIEnv* pEnv, Thread* self)
116{
117    ((JNIEnvExt*)pEnv)->envThreadId = self->threadId;
118    ((JNIEnvExt*)pEnv)->self = self;
119}
120
121/*
122 * JNI call bridges.  Not usually called directly.
123 *
124 * The "Check" versions are used when CheckJNI is enabled.
125 */
126void dvmCallJNIMethod(const u4* args, JValue* pResult, const Method* method,
127    Thread* self);
128void dvmCallSynchronizedJNIMethod(const u4* args, JValue* pResult,
129    const Method* method, Thread* self);
130void dvmCheckCallJNIMethod(const u4* args, JValue* pResult,
131    const Method* method, Thread* self);
132void dvmCheckCallSynchronizedJNIMethod(const u4* args, JValue* pResult,
133    const Method* method, Thread* self);
134
135/*
136 * Configure "method" to use the JNI bridge to call "func".
137 */
138void dvmUseJNIBridge(Method* method, void* func);
139
140
141/*
142 * Enable the "checked" versions.
143 */
144void dvmUseCheckedJniEnv(JNIEnvExt* pEnv);
145void dvmUseCheckedJniVm(JavaVMExt* pVm);
146void dvmLateEnableCheckedJni(void);
147
148/*
149 * Verify that a reference passed in from native code is valid.  Returns
150 * an indication of local/global/invalid.
151 */
152jobjectRefType dvmGetJNIRefType(Object* obj);
153
154/*
155 * Get the last method called on the interp stack.  This is the method
156 * "responsible" for calling into JNI.
157 */
158const Method* dvmGetCurrentJNIMethod(void);
159
160/*
161 * Create/destroy a JNIEnv for the current thread.
162 */
163JNIEnv* dvmCreateJNIEnv(Thread* self);
164void dvmDestroyJNIEnv(JNIEnv* env);
165
166/*
167 * Find the JNIEnv associated with the current thread.
168 */
169JNIEnvExt* dvmGetJNIEnvForThread(void);
170
171/*
172 * Extract the return type enum from the "jniArgInfo" value.
173 */
174DalvikJniReturnType dvmGetArgInfoReturnType(int jniArgInfo);
175
176/*
177 * Release all MonitorEnter-acquired locks that are still held.  Called at
178 * DetachCurrentThread time.
179 */
180void dvmReleaseJniMonitors(Thread* self);
181
182#endif /*_DALVIK_JNIINTERNAL*/
183