Parcel.h revision f4c1088d750a182bd85889c86b3c9ef4ba772405 
1/*
2 * Copyright (C) 2005 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#ifndef ANDROID_PARCEL_H
18#define ANDROID_PARCEL_H
19
20#include <cutils/native_handle.h>
21#include <utils/Errors.h>
22#include <utils/RefBase.h>
23#include <utils/String16.h>
24#include <utils/Vector.h>
25
26// ---------------------------------------------------------------------------
27namespace android {
28
29class Flattenable;
30class IBinder;
31class IPCThreadState;
32class ProcessState;
33class String8;
34class TextOutput;
35
36struct flat_binder_object;  // defined in support_p/binder_module.h
37
38class Parcel
39{
40public:
41    class ReadableBlob;
42    class WritableBlob;
43
44                        Parcel();
45                        ~Parcel();
46
47    const uint8_t*      data() const;
48    size_t              dataSize() const;
49    size_t              dataAvail() const;
50    size_t              dataPosition() const;
51    size_t              dataCapacity() const;
52
53    status_t            setDataSize(size_t size);
54    void                setDataPosition(size_t pos) const;
55    status_t            setDataCapacity(size_t size);
56
57    status_t            setData(const uint8_t* buffer, size_t len);
58
59    status_t            appendFrom(const Parcel *parcel,
60                                   size_t start, size_t len);
61
62    bool                hasFileDescriptors() const;
63
64    // Writes the RPC header.
65    status_t            writeInterfaceToken(const String16& interface);
66
67    // Parses the RPC header, returning true if the interface name
68    // in the header matches the expected interface from the caller.
69    //
70    // Additionally, enforceInterface does part of the work of
71    // propagating the StrictMode policy mask, populating the current
72    // IPCThreadState, which as an optimization may optionally be
73    // passed in.
74    bool                enforceInterface(const String16& interface,
75                                         IPCThreadState* threadState = NULL) const;
76    bool                checkInterface(IBinder*) const;
77
78    void                freeData();
79
80    const size_t*       objects() const;
81    size_t              objectsCount() const;
82
83    status_t            errorCheck() const;
84    void                setError(status_t err);
85
86    status_t            write(const void* data, size_t len);
87    void*               writeInplace(size_t len);
88    status_t            writeUnpadded(const void* data, size_t len);
89    status_t            writeInt32(int32_t val);
90    status_t            writeInt64(int64_t val);
91    status_t            writeFloat(float val);
92    status_t            writeDouble(double val);
93    status_t            writeIntPtr(intptr_t val);
94    status_t            writeCString(const char* str);
95    status_t            writeString8(const String8& str);
96    status_t            writeString16(const String16& str);
97    status_t            writeString16(const char16_t* str, size_t len);
98    status_t            writeStrongBinder(const sp<IBinder>& val);
99    status_t            writeWeakBinder(const wp<IBinder>& val);
100    status_t            write(const Flattenable& val);
101
102    // Place a native_handle into the parcel (the native_handle's file-
103    // descriptors are dup'ed, so it is safe to delete the native_handle
104    // when this function returns).
105    // Doesn't take ownership of the native_handle.
106    status_t            writeNativeHandle(const native_handle* handle);
107
108    // Place a file descriptor into the parcel.  The given fd must remain
109    // valid for the lifetime of the parcel.
110    status_t            writeFileDescriptor(int fd);
111
112    // Place a file descriptor into the parcel.  A dup of the fd is made, which
113    // will be closed once the parcel is destroyed.
114    status_t            writeDupFileDescriptor(int fd);
115
116    // Writes a blob to the parcel.
117    // If the blob is small, then it is stored in-place, otherwise it is
118    // transferred by way of an anonymous shared memory region.
119    // The caller should call release() on the blob after writing its contents.
120    status_t            writeBlob(size_t len, WritableBlob* outBlob);
121
122    status_t            writeObject(const flat_binder_object& val, bool nullMetaData);
123
124    // Like Parcel.java's writeNoException().  Just writes a zero int32.
125    // Currently the native implementation doesn't do any of the StrictMode
126    // stack gathering and serialization that the Java implementation does.
127    status_t            writeNoException();
128
129    void                remove(size_t start, size_t amt);
130
131    status_t            read(void* outData, size_t len) const;
132    const void*         readInplace(size_t len) const;
133    int32_t             readInt32() const;
134    status_t            readInt32(int32_t *pArg) const;
135    int64_t             readInt64() const;
136    status_t            readInt64(int64_t *pArg) const;
137    float               readFloat() const;
138    status_t            readFloat(float *pArg) const;
139    double              readDouble() const;
140    status_t            readDouble(double *pArg) const;
141    intptr_t            readIntPtr() const;
142    status_t            readIntPtr(intptr_t *pArg) const;
143
144    const char*         readCString() const;
145    String8             readString8() const;
146    String16            readString16() const;
147    const char16_t*     readString16Inplace(size_t* outLen) const;
148    sp<IBinder>         readStrongBinder() const;
149    wp<IBinder>         readWeakBinder() const;
150    status_t            read(Flattenable& val) const;
151
152    // Like Parcel.java's readExceptionCode().  Reads the first int32
153    // off of a Parcel's header, returning 0 or the negative error
154    // code on exceptions, but also deals with skipping over rich
155    // response headers.  Callers should use this to read & parse the
156    // response headers rather than doing it by hand.
157    int32_t             readExceptionCode() const;
158
159    // Retrieve native_handle from the parcel. This returns a copy of the
160    // parcel's native_handle (the caller takes ownership). The caller
161    // must free the native_handle with native_handle_close() and
162    // native_handle_delete().
163    native_handle*     readNativeHandle() const;
164
165
166    // Retrieve a file descriptor from the parcel.  This returns the raw fd
167    // in the parcel, which you do not own -- use dup() to get your own copy.
168    int                 readFileDescriptor() const;
169
170    // Reads a blob from the parcel.
171    // The caller should call release() on the blob after reading its contents.
172    status_t            readBlob(size_t len, ReadableBlob* outBlob) const;
173
174    const flat_binder_object* readObject(bool nullMetaData) const;
175
176    // Explicitly close all file descriptors in the parcel.
177    void                closeFileDescriptors();
178
179    typedef void        (*release_func)(Parcel* parcel,
180                                        const uint8_t* data, size_t dataSize,
181                                        const size_t* objects, size_t objectsSize,
182                                        void* cookie);
183
184    const uint8_t*      ipcData() const;
185    size_t              ipcDataSize() const;
186    const size_t*       ipcObjects() const;
187    size_t              ipcObjectsCount() const;
188    void                ipcSetDataReference(const uint8_t* data, size_t dataSize,
189                                            const size_t* objects, size_t objectsCount,
190                                            release_func relFunc, void* relCookie);
191
192    void                print(TextOutput& to, uint32_t flags = 0) const;
193
194private:
195                        Parcel(const Parcel& o);
196    Parcel&             operator=(const Parcel& o);
197
198    status_t            finishWrite(size_t len);
199    void                releaseObjects();
200    void                acquireObjects();
201    status_t            growData(size_t len);
202    status_t            restartWrite(size_t desired);
203    status_t            continueWrite(size_t desired);
204    void                freeDataNoInit();
205    void                initState();
206    void                scanForFds() const;
207
208    template<class T>
209    status_t            readAligned(T *pArg) const;
210
211    template<class T>   T readAligned() const;
212
213    template<class T>
214    status_t            writeAligned(T val);
215
216    status_t            mError;
217    uint8_t*            mData;
218    size_t              mDataSize;
219    size_t              mDataCapacity;
220    mutable size_t      mDataPos;
221    size_t*             mObjects;
222    size_t              mObjectsSize;
223    size_t              mObjectsCapacity;
224    mutable size_t      mNextObjectHint;
225
226    mutable bool        mFdsKnown;
227    mutable bool        mHasFds;
228
229    release_func        mOwner;
230    void*               mOwnerCookie;
231
232    class Blob {
233    public:
234        Blob();
235        ~Blob();
236
237        void release();
238        inline size_t size() const { return mSize; }
239
240    protected:
241        void init(bool mapped, void* data, size_t size);
242        void clear();
243
244        bool mMapped;
245        void* mData;
246        size_t mSize;
247    };
248
249public:
250    class ReadableBlob : public Blob {
251        friend class Parcel;
252    public:
253        inline const void* data() const { return mData; }
254    };
255
256    class WritableBlob : public Blob {
257        friend class Parcel;
258    public:
259        inline void* data() { return mData; }
260    };
261};
262
263// ---------------------------------------------------------------------------
264
265inline TextOutput& operator<<(TextOutput& to, const Parcel& parcel)
266{
267    parcel.print(to);
268    return to;
269}
270
271// ---------------------------------------------------------------------------
272
273// Generic acquire and release of objects.
274void acquire_object(const sp<ProcessState>& proc,
275                    const flat_binder_object& obj, const void* who);
276void release_object(const sp<ProcessState>& proc,
277                    const flat_binder_object& obj, const void* who);
278
279void flatten_binder(const sp<ProcessState>& proc,
280                    const sp<IBinder>& binder, flat_binder_object* out);
281void flatten_binder(const sp<ProcessState>& proc,
282                    const wp<IBinder>& binder, flat_binder_object* out);
283status_t unflatten_binder(const sp<ProcessState>& proc,
284                          const flat_binder_object& flat, sp<IBinder>* out);
285status_t unflatten_binder(const sp<ProcessState>& proc,
286                          const flat_binder_object& flat, wp<IBinder>* out);
287
288}; // namespace android
289
290// ---------------------------------------------------------------------------
291
292#endif // ANDROID_PARCEL_H
293