Parcel.h revision f0190bff38b6c29abbfc4a877442f71fc3d7dad8 
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#include <utils/Flattenable.h>
26
27// ---------------------------------------------------------------------------
28namespace android {
29
30template <typename T> class Flattenable;
31template <typename T> class LightFlattenable;
32class IBinder;
33class IPCThreadState;
34class ProcessState;
35class String8;
36class TextOutput;
37
38struct flat_binder_object;  // defined in support_p/binder_module.h
39
40class Parcel {
41public:
42    class ReadableBlob;
43    class WritableBlob;
44
45                        Parcel();
46                        ~Parcel();
47
48    const uint8_t*      data() const;
49    size_t              dataSize() const;
50    size_t              dataAvail() const;
51    size_t              dataPosition() const;
52    size_t              dataCapacity() const;
53
54    status_t            setDataSize(size_t size);
55    void                setDataPosition(size_t pos) const;
56    status_t            setDataCapacity(size_t size);
57
58    status_t            setData(const uint8_t* buffer, size_t len);
59
60    status_t            appendFrom(const Parcel *parcel,
61                                   size_t start, size_t len);
62
63    bool                pushAllowFds(bool allowFds);
64    void                restoreAllowFds(bool lastValue);
65
66    bool                hasFileDescriptors() const;
67
68    // Writes the RPC header.
69    status_t            writeInterfaceToken(const String16& interface);
70
71    // Parses the RPC header, returning true if the interface name
72    // in the header matches the expected interface from the caller.
73    //
74    // Additionally, enforceInterface does part of the work of
75    // propagating the StrictMode policy mask, populating the current
76    // IPCThreadState, which as an optimization may optionally be
77    // passed in.
78    bool                enforceInterface(const String16& interface,
79                                         IPCThreadState* threadState = NULL) const;
80    bool                checkInterface(IBinder*) const;
81
82    void                freeData();
83
84    const size_t*       objects() const;
85    size_t              objectsCount() const;
86
87    status_t            errorCheck() const;
88    void                setError(status_t err);
89
90    status_t            write(const void* data, size_t len);
91    void*               writeInplace(size_t len);
92    status_t            writeUnpadded(const void* data, size_t len);
93    status_t            writeInt32(int32_t val);
94    status_t            writeInt64(int64_t val);
95    status_t            writeFloat(float val);
96    status_t            writeDouble(double val);
97    status_t            writeIntPtr(intptr_t val);
98    status_t            writeCString(const char* str);
99    status_t            writeString8(const String8& str);
100    status_t            writeString16(const String16& str);
101    status_t            writeString16(const char16_t* str, size_t len);
102    status_t            writeStrongBinder(const sp<IBinder>& val);
103    status_t            writeWeakBinder(const wp<IBinder>& val);
104    status_t            writeInt32Array(size_t len, const int32_t *val);
105    status_t            writeByteArray(size_t len, const uint8_t *val);
106
107    template<typename T>
108    status_t            write(const Flattenable<T>& val);
109
110    template<typename T>
111    status_t            write(const LightFlattenable<T>& val);
112
113
114    // Place a native_handle into the parcel (the native_handle's file-
115    // descriptors are dup'ed, so it is safe to delete the native_handle
116    // when this function returns).
117    // Doesn't take ownership of the native_handle.
118    status_t            writeNativeHandle(const native_handle* handle);
119
120    // Place a file descriptor into the parcel.  The given fd must remain
121    // valid for the lifetime of the parcel.
122    // The Parcel does not take ownership of the given fd unless you ask it to.
123    status_t            writeFileDescriptor(int fd, bool takeOwnership = false);
124
125    // Place a file descriptor into the parcel.  A dup of the fd is made, which
126    // will be closed once the parcel is destroyed.
127    status_t            writeDupFileDescriptor(int fd);
128
129    // Writes a blob to the parcel.
130    // If the blob is small, then it is stored in-place, otherwise it is
131    // transferred by way of an anonymous shared memory region.
132    // The caller should call release() on the blob after writing its contents.
133    status_t            writeBlob(size_t len, WritableBlob* outBlob);
134
135    status_t            writeObject(const flat_binder_object& val, bool nullMetaData);
136
137    // Like Parcel.java's writeNoException().  Just writes a zero int32.
138    // Currently the native implementation doesn't do any of the StrictMode
139    // stack gathering and serialization that the Java implementation does.
140    status_t            writeNoException();
141
142    void                remove(size_t start, size_t amt);
143
144    status_t            read(void* outData, size_t len) const;
145    const void*         readInplace(size_t len) const;
146    int32_t             readInt32() const;
147    status_t            readInt32(int32_t *pArg) const;
148    int64_t             readInt64() const;
149    status_t            readInt64(int64_t *pArg) const;
150    float               readFloat() const;
151    status_t            readFloat(float *pArg) const;
152    double              readDouble() const;
153    status_t            readDouble(double *pArg) const;
154    intptr_t            readIntPtr() const;
155    status_t            readIntPtr(intptr_t *pArg) const;
156
157    const char*         readCString() const;
158    String8             readString8() const;
159    String16            readString16() const;
160    const char16_t*     readString16Inplace(size_t* outLen) const;
161    sp<IBinder>         readStrongBinder() const;
162    wp<IBinder>         readWeakBinder() const;
163
164    template<typename T>
165    status_t            read(Flattenable<T>& val) const;
166
167    template<typename T>
168    status_t            read(LightFlattenable<T>& val) const;
169
170    // Like Parcel.java's readExceptionCode().  Reads the first int32
171    // off of a Parcel's header, returning 0 or the negative error
172    // code on exceptions, but also deals with skipping over rich
173    // response headers.  Callers should use this to read & parse the
174    // response headers rather than doing it by hand.
175    int32_t             readExceptionCode() const;
176
177    // Retrieve native_handle from the parcel. This returns a copy of the
178    // parcel's native_handle (the caller takes ownership). The caller
179    // must free the native_handle with native_handle_close() and
180    // native_handle_delete().
181    native_handle*     readNativeHandle() const;
182
183
184    // Retrieve a file descriptor from the parcel.  This returns the raw fd
185    // in the parcel, which you do not own -- use dup() to get your own copy.
186    int                 readFileDescriptor() const;
187
188    // Reads a blob from the parcel.
189    // The caller should call release() on the blob after reading its contents.
190    status_t            readBlob(size_t len, ReadableBlob* outBlob) const;
191
192    const flat_binder_object* readObject(bool nullMetaData) const;
193
194    // Explicitly close all file descriptors in the parcel.
195    void                closeFileDescriptors();
196
197    typedef void        (*release_func)(Parcel* parcel,
198                                        const uint8_t* data, size_t dataSize,
199                                        const size_t* objects, size_t objectsSize,
200                                        void* cookie);
201
202    const uint8_t*      ipcData() const;
203    size_t              ipcDataSize() const;
204    const size_t*       ipcObjects() const;
205    size_t              ipcObjectsCount() const;
206    void                ipcSetDataReference(const uint8_t* data, size_t dataSize,
207                                            const size_t* objects, size_t objectsCount,
208                                            release_func relFunc, void* relCookie);
209
210    void                print(TextOutput& to, uint32_t flags = 0) const;
211
212private:
213                        Parcel(const Parcel& o);
214    Parcel&             operator=(const Parcel& o);
215
216    status_t            finishWrite(size_t len);
217    void                releaseObjects();
218    void                acquireObjects();
219    status_t            growData(size_t len);
220    status_t            restartWrite(size_t desired);
221    status_t            continueWrite(size_t desired);
222    void                freeDataNoInit();
223    void                initState();
224    void                scanForFds() const;
225
226    template<class T>
227    status_t            readAligned(T *pArg) const;
228
229    template<class T>   T readAligned() const;
230
231    template<class T>
232    status_t            writeAligned(T val);
233
234    status_t            mError;
235    uint8_t*            mData;
236    size_t              mDataSize;
237    size_t              mDataCapacity;
238    mutable size_t      mDataPos;
239    size_t*             mObjects;
240    size_t              mObjectsSize;
241    size_t              mObjectsCapacity;
242    mutable size_t      mNextObjectHint;
243
244    mutable bool        mFdsKnown;
245    mutable bool        mHasFds;
246    bool                mAllowFds;
247
248    release_func        mOwner;
249    void*               mOwnerCookie;
250
251    class Blob {
252    public:
253        Blob();
254        ~Blob();
255
256        void release();
257        inline size_t size() const { return mSize; }
258
259    protected:
260        void init(bool mapped, void* data, size_t size);
261        void clear();
262
263        bool mMapped;
264        void* mData;
265        size_t mSize;
266    };
267
268    class FlattenableHelperInterface {
269    protected:
270        ~FlattenableHelperInterface() { }
271    public:
272        virtual size_t getFlattenedSize() const = 0;
273        virtual size_t getFdCount() const = 0;
274        virtual status_t flatten(void* buffer, size_t size, int* fds, size_t count) const = 0;
275        virtual status_t unflatten(void const* buffer, size_t size, int const* fds, size_t count) = 0;
276    };
277
278    template<typename T>
279    class FlattenableHelper : public FlattenableHelperInterface {
280        friend class Parcel;
281        const Flattenable<T>& val;
282        explicit FlattenableHelper(const Flattenable<T>& val) : val(val) { }
283
284    public:
285        virtual size_t getFlattenedSize() const {
286            return val.getFlattenedSize();
287        }
288        virtual size_t getFdCount() const {
289            return val.getFdCount();
290        }
291        virtual status_t flatten(void* buffer, size_t size, int* fds, size_t count) const {
292            return val.flatten(buffer, size, fds, count);
293        }
294        virtual status_t unflatten(void const* buffer, size_t size, int const* fds, size_t count) {
295            return const_cast<Flattenable<T>&>(val).unflatten(buffer, size, fds, count);
296        }
297    };
298    status_t write(const FlattenableHelperInterface& val);
299    status_t read(FlattenableHelperInterface& val) const;
300
301public:
302    class ReadableBlob : public Blob {
303        friend class Parcel;
304    public:
305        inline const void* data() const { return mData; }
306    };
307
308    class WritableBlob : public Blob {
309        friend class Parcel;
310    public:
311        inline void* data() { return mData; }
312    };
313};
314
315// ---------------------------------------------------------------------------
316
317template<typename T>
318status_t Parcel::write(const Flattenable<T>& val) {
319    const FlattenableHelper<T> helper(val);
320    return write(helper);
321}
322
323template<typename T>
324status_t Parcel::write(const LightFlattenable<T>& val) {
325    size_t size(val.getFlattenedSize());
326    if (!val.isFixedSize()) {
327        status_t err = writeInt32(size);
328        if (err != NO_ERROR) {
329            return err;
330        }
331    }
332    if (size) {
333        void* buffer = writeInplace(size);
334        if (buffer == NULL)
335            return NO_MEMORY;
336        return val.flatten(buffer, size);
337    }
338    return NO_ERROR;
339}
340
341template<typename T>
342status_t Parcel::read(Flattenable<T>& val) const {
343    FlattenableHelper<T> helper(val);
344    return read(helper);
345}
346
347template<typename T>
348status_t Parcel::read(LightFlattenable<T>& val) const {
349    size_t size;
350    if (val.isFixedSize()) {
351        size = val.getFlattenedSize();
352    } else {
353        int32_t s;
354        status_t err = readInt32(&s);
355        if (err != NO_ERROR) {
356            return err;
357        }
358        size = s;
359    }
360    if (size) {
361        void const* buffer = readInplace(size);
362        return buffer == NULL ? NO_MEMORY :
363                val.unflatten(buffer, size);
364    }
365    return NO_ERROR;
366}
367
368// ---------------------------------------------------------------------------
369
370inline TextOutput& operator<<(TextOutput& to, const Parcel& parcel)
371{
372    parcel.print(to);
373    return to;
374}
375
376// ---------------------------------------------------------------------------
377
378// Generic acquire and release of objects.
379void acquire_object(const sp<ProcessState>& proc,
380                    const flat_binder_object& obj, const void* who);
381void release_object(const sp<ProcessState>& proc,
382                    const flat_binder_object& obj, const void* who);
383
384void flatten_binder(const sp<ProcessState>& proc,
385                    const sp<IBinder>& binder, flat_binder_object* out);
386void flatten_binder(const sp<ProcessState>& proc,
387                    const wp<IBinder>& binder, flat_binder_object* out);
388status_t unflatten_binder(const sp<ProcessState>& proc,
389                          const flat_binder_object& flat, sp<IBinder>* out);
390status_t unflatten_binder(const sp<ProcessState>& proc,
391                          const flat_binder_object& flat, wp<IBinder>* out);
392
393}; // namespace android
394
395// ---------------------------------------------------------------------------
396
397#endif // ANDROID_PARCEL_H
398