Android中的Parcel机制LOGE("null proxy"); }

LOGE("null proxy");
}
const int32_t handle = proxy ? proxy->handle() : 0;
obj.type = BINDER_TYPE_WEAK_HANDLE;
obj.handle = handle;
obj.cookie = NULL;
} else {
obj.type = BINDER_TYPE_WEAK_BINDER;
obj.binder = binder.get_refs();
obj.cookie = binder.unsafe_get();
}
return finish_flatten_binder(real, obj, out);
}
// XXX How to deal? In order to flatten the given binder,
// we need to probe it for information, which requires a primary
// reference... but we don't have one.
//
// The OpenBinder implementation uses a dynamic_cast<> here,
// but we can't do that with the different reference counting
// implementation we are using.
LOGE("Unable to unflatten Binder weak reference!");
obj.type = BINDER_TYPE_BINDER;
obj.binder = NULL;
obj.cookie = NULL;
return finish_flatten_binder(NULL, obj, out);
} else {
obj.type = BINDER_TYPE_BINDER;
obj.binder = NULL;
obj.cookie = NULL;
return finish_flatten_binder(NULL, obj, out);
}
}
inline static status_t finish_unflatten_binder(
BpBinder* proxy, const flat_binder_object& flat, const Parcel& in)
{
return NO_ERROR;
}
status_t unflatten_binder(const sp& proc,
const Parcel& in, sp* out)
{
const flat_binder_object* flat = in.readObject(false);
if (flat) {
switch (flat->type) {
case BINDER_TYPE_BINDER:
*out = static_cast<IBinder*>(flat->cookie);
return finish_unflatten_binder(NULL, *flat, in);
case BINDER_TYPE_HANDLE:
*out = proc->getStrongProxyForHandle(flat->handle);
return finish_unflatten_binder(
static_cast<BpBinder*>(out->get()), *flat, in);
}
}
return BAD_TYPE;
}
status_t unflatten_binder(const sp& proc,
const Parcel& in, wp* out)
{
const flat_binder_object* flat = in.readObject(false);
if (flat) {
switch (flat->type) {
case BINDER_TYPE_BINDER:
*out = static_cast<IBinder*>(flat->cookie);
return finish_unflatten_binder(NULL, *flat, in);
case BINDER_TYPE_WEAK_BINDER:
if (flat->binder != NULL) {
out->set_object_and_refs(
static_cast<IBinder*>(flat->cookie),
static_castRefBase::weakref\_type\*(flat->binder));
} else {
*out = NULL;
}
return finish_unflatten_binder(NULL, *flat, in);
case BINDER_TYPE_HANDLE:
case BINDER_TYPE_WEAK_HANDLE:
*out = proc->getWeakProxyForHandle(flat->handle);
return finish_unflatten_binder(
static_cast<BpBinder*>(out->unsafe_get()), *flat, in);
}
}
return BAD_TYPE;
}
// ---------------------------------------------------------------------------
Parcel::Parcel()
{
initState();
}
Parcel::~Parcel()
{
freeDataNoInit();
}
const uint8_t* Parcel::data() const
{
return mData;
}
size_t Parcel::dataSize() const
{
return (mDataSize > mDataPos ? mDataSize : mDataPos);
}
size_t Parcel::dataAvail() const
{
// TODO: decide what to do about the possibility that this can
// report an available-data size that exceeds a Java int's max
// positive value, causing havoc. Fortunately this will only
// happen if someone constructs a Parcel containing more than two
// gigabytes of data, which on typical phone hardware is simply
// not possible.
return dataSize() - dataPosition();
}
size_t Parcel::dataPosition() const
{
return mDataPos;
}
size_t Parcel::dataCapacity() const
{
return mDataCapacity;
}
status_t Parcel::setDataSize(size_t size)
{
status_t err;
err = continueWrite(size);
if (err == NO_ERROR) {
mDataSize = size;
LOGV("setDataSize Setting data size of %p to %d/n", this, mDataSize);
}
return err;
}
void Parcel::setDataPosition(size_t pos) const
{
mDataPos = pos;
mNextObjectHint = 0;
}
status_t Parcel::setDataCapacity(size_t size)
{
if (size > mDataSize) return continueWrite(size);
return NO_ERROR;
}
status_t Parcel::setData(const uint8_t* buffer, size_t len)
{
status_t err = restartWrite(len);
if (err == NO_ERROR) {
memcpy(const_cast<uint8_t*>(data()), buffer, len);
mDataSize = len;
mFdsKnown = false;
}
return err;
}
status_t Parcel::appendFrom(Parcel *parcel, size_t offset, size_t len)
{
const sp proc(ProcessState::self());
status_t err;
uint8_t *data = parcel->mData;
size_t *objects = parcel->mObjects;
size_t size = parcel->mObjectsSize;
int startPos = mDataPos;
int firstIndex = -1, lastIndex = -2;
if (len == 0) {
return NO_ERROR;
}
// range checks against the source parcel size
if ((offset > parcel->mDataSize)
|| (len > parcel->mDataSize)
|| (offset + len > parcel->mDataSize)) {
return BAD_VALUE;
}
// Count objects in range
for (int i = 0; i < (int) size; i++) {
size_t off = objects[i];
if ((off >= offset) && (off < offset + len)) {
if (firstIndex == -1) {
firstIndex = i;
}
lastIndex = i;
}
}
int numObjects = lastIndex - firstIndex + 1;
// grow data
err = growData(len);
if (err != NO_ERROR) {
return err;
}
// append data
memcpy(mData + mDataPos, data + offset, len);
mDataPos += len;
mDataSize += len;
if (numObjects > 0) {
// grow objects
if (mObjectsCapacity < mObjectsSize + numObjects) {
int newSize = ((mObjectsSize + numObjects)*3)/2;
size_t *objects =
(size_t*)realloc(mObjects, newSize*sizeof(size_t));
if (objects == (size_t*)0) {
return NO_MEMORY;
}
mObjects = objects;
mObjectsCapacity = newSize;
}
// append and acquire objects
int idx = mObjectsSize;
for (int i = firstIndex; i <= lastIndex; i++) {
size_t off = objects[i] - offset + startPos;
mObjects[idx++] = off;
mObjectsSize++;
flat_binder_object* flat
= reinterpret_cast<flat_binder_object*>(mData + off);
acquire_object(proc, *flat, this);
if (flat->type == BINDER_TYPE_FD) {
// If this is a file descriptor, we need to dup it so the
// new Parcel now owns its own fd, and can declare that we
// officially know we have fds.
flat->handle = dup(flat->handle);
flat->cookie = (void*)1;
mHasFds = mFdsKnown = true;
}
}
}
return NO_ERROR;
}
bool Parcel::hasFileDescriptors() const
{
if (!mFdsKnown) {
scanForFds();
}
return mHasFds;
}
status_t Parcel::writeInterfaceToken(const String16& interface)
{
// currently the interface identification token is just its name as a string
return writeString16(interface);
}
bool Parcel::checkInterface(IBinder* binder) const
{
return enforceInterface(binder->getInterfaceDescriptor());
}
bool Parcel::enforceInterface(const String16& interface) const
{
const String16 str(readString16());
if (str == interface) {
return true;
} else {
LOGW("**** enforceInterface() expected '%s' but read '%s'/n",
String8(interface).string(), String8(str).string());
return false;
}
}
const size_t* Parcel::objects() const
{
return mObjects;
}
size_t Parcel::objectsCount() const
{
return mObjectsSize;
}
status_t Parcel::errorCheck() const
{
return mError;
}
void Parcel::setError(status_t err)
{
mError = err;
}
status_t Parcel::finishWrite(size_t len)
{
//printf("Finish write of %d/n", len);
mDataPos += len;
LOGV("finishWrite Setting data pos of %p to %d/n", this, mDataPos);
if (mDataPos > mDataSize) {
mDataSize = mDataPos;
LOGV("finishWrite Setting data size of %p to %d/n", this, mDataSize);
}
//printf("New pos=%d, size=%d/n", mDataPos, mDataSize);
return NO_ERROR;
}
status_t Parcel::writeUnpadded(const void* data, size_t len)
{
size_t end = mDataPos + len;
if (end < mDataPos) {
// integer overflow
return BAD_VALUE;
}
if (end <= mDataCapacity) {
restart_write:
memcpy(mData+mDataPos, data, len);
return finishWrite(len);
}
status_t err = growData(len);
if (err == NO_ERROR) goto restart_write;
return err;
}
status_t Parcel::write(const void* data, size_t len)
{
void* const d = writeInplace(len);
if (d) {
memcpy(d, data, len);
return NO_ERROR;
}
return mError;
}
void* Parcel::writeInplace(size_t len)
{
const size_t padded = PAD_SIZE(len);
// sanity check for integer overflow
if (mDataPos+padded < mDataPos) {
return NULL;
}
if ((mDataPos+padded) <= mDataCapacity) {
restart_write:
//printf("Writing %ld bytes, padded to %ld/n", len, padded);
uint8_t* const data = mData+mDataPos;
// Need to pad at end?
if (padded != len) {
#if BYTE_ORDER == BIG_ENDIAN
static const uint32_t mask[4] = {
0x00000000, 0xffffff00, 0xffff0000, 0xff000000
};
#endif
#if BYTE_ORDER == LITTLE_ENDIAN
static const uint32_t mask[4] = {
0x00000000, 0x00ffffff, 0x0000ffff, 0x000000ff
};
#endif
//printf("Applying pad mask: %p to %p/n", (void*)mask[padded-len],
// *reinterpret_cast<void**>(data+padded-4));
*reinterpret_cast<uint32_t*>(data+padded-4) &= mask[padded-len];
}
finishWrite(padded);
return data;
}
status_t err = growData(padded);
if (err == NO_ERROR) goto restart_write;
return NULL;
}
status_t Parcel::writeInt32(int32_t val)
{
return writeAligned(val);
}
status_t Parcel::writeInt64(int64_t val)
{
return writeAligned(val);
}
status_t Parcel::writeFloat(float val)
{
return writeAligned(val);
}
status_t Parcel::writeDouble(double val)
{
return writeAligned(val);
}
status_t Parcel::writeIntPtr(intptr_t val)
{
return writeAligned(val);
}
status_t Parcel::writeCString(const char* str)
{
return write(str, strlen(str)+1);
}
status_t Parcel::writeString8(const String8& str)
{
status_t err = writeInt32(str.bytes());
if (err == NO_ERROR) {
err = write(str.string(), str.bytes()+1);
}
return err;
}
status_t Parcel::writeString16(const String16& str)
{
return writeString16(str.string(), str.size());
}
status_t Parcel::writeString16(const char16_t* str, size_t len)
{
if (str == NULL) return writeInt32(-1);
status_t err = writeInt32(len);
if (err == NO_ERROR) {
len *= sizeof(char16_t);
uint8_t* data = (uint8_t*)writeInplace(len+sizeof(char16_t));
if (data) {
memcpy(data, str, len);
*reinterpret_cast<char16_t*>(data+len) = 0;
return NO_ERROR;
}
err = mError;
}
return err;
}
status_t Parcel::writeStrongBinder(const sp& val)
{
return flatten_binder(ProcessState::self(), val, this);
}
status_t Parcel::writeWeakBinder(const wp& val)
{
return flatten_binder(ProcessState::self(), val, this);
}
status_t Parcel::writeNativeHandle(const native_handle* handle)
{
if (!handle || handle->version != sizeof(native_handle))
return BAD_TYPE;
status_t err;
err = writeInt32(handle->numFds);
if (err != NO_ERROR) return err;
err = writeInt32(handle->numInts);
if (err != NO_ERROR) return err;
for (int i=0 ; err==NO_ERROR && inumFds ; i++)
err = writeDupFileDescriptor(handle->data[i]);
if (err != NO_ERROR) {
LOGD("write native handle, write dup fd failed");
return err;
}
err = write(handle->data + handle->numFds, sizeof(int)*handle->numInts);
return err;
}
status_t Parcel::writeFileDescriptor(int fd)
{
flat_binder_object obj;
obj.type = BINDER_TYPE_FD;
obj.flags = 0x7f | FLAT_BINDER_FLAG_ACCEPTS_FDS;
obj.handle = fd;
obj.cookie = (void*)0;
return writeObject(obj, true);
}
status_t Parcel::writeDupFileDescriptor(int fd)
{
flat_binder_object obj;
obj.type = BINDER_TYPE_FD;
obj.flags = 0x7f | FLAT_BINDER_FLAG_ACCEPTS_FDS;
obj.handle = dup(fd);
obj.cookie = (void*)1;
return writeObject(obj, true);
}
status_t Parcel::write(const Flattenable& val)
{
status_t err;
// size if needed
size_t len = val.getFlattenedSize();
size_t fd_count = val.getFdCount();
err = this->writeInt32(len);
if (err) return err;
err = this->writeInt32(fd_count);
if (err) return err;
// payload
void* buf = this->writeInplace(PAD_SIZE(len));
if (buf == NULL)
return BAD_VALUE;
int* fds = NULL;
if (fd_count) {
fds = new int[fd_count];
}
err = val.flatten(buf, len, fds, fd_count);
for (size_t i=0 ; i<fd_count && err==NO_ERROR ; i++) {
err = this->writeDupFileDescriptor( fds[i] );
}
if (fd_count) {
delete [] fds;
}
return err;
}
status_t Parcel::writeObject(const flat_binder_object& val, bool nullMetaData)
{
const bool enoughData = (mDataPos+sizeof(val)) <= mDataCapacity;
const bool enoughObjects = mObjectsSize < mObjectsCapacity;
if (enoughData && enoughObjects) {
restart_write:
*reinterpret_cast<flat_binder_object*>(mData+mDataPos) = val;
// Need to write meta-data?
if (nullMetaData || val.binder != NULL) {
mObjects[mObjectsSize] = mDataPos;
acquire_object(ProcessState::self(), val, this);
mObjectsSize++;
}
// remember if it's a file descriptor
if (val.type == BINDER_TYPE_FD) {
mHasFds = mFdsKnown = true;
}
return finishWrite(sizeof(flat_binder_object));
}
if (!enoughData) {
const status_t err = growData(sizeof(val));
if (err != NO_ERROR) return err;
}
if (!enoughObjects) {
size_t newSize = ((mObjectsSize+2)*3)/2;
size_t* objects = (size_t*)realloc(mObjects, newSize*sizeof(size_t));
if (objects == NULL) return NO_MEMORY;
mObjects = objects;
mObjectsCapacity = newSize;
}
goto restart_write;
}
void Parcel::remove(size_t start, size_t amt)
{
LOG_ALWAYS_FATAL("Parcel::remove() not yet implemented!");
}
status_t Parcel::read(void* outData, size_t len) const
{
if ((mDataPos+PAD_SIZE(len)) >= mDataPos && (mDataPos+PAD_SIZE(len)) <= mDataSize) {
memcpy(outData, mData+mDataPos, len);
mDataPos += PAD_SIZE(len);
LOGV("read Setting data pos of %p to %d/n", this, mDataPos);
return NO_ERROR;
}
return NOT_ENOUGH_DATA;
}
const void* Parcel::readInplace(size_t len) const
{
if ((mDataPos+PAD_SIZE(len)) >= mDataPos && (mDataPos+PAD_SIZE(len)) <= mDataSize) {
const void* data = mData+mDataPos;
mDataPos += PAD_SIZE(len);
LOGV("readInplace Setting data pos of %p to %d/n", this, mDataPos);
return data;
}
return NULL;
}
template<class T>
status_t Parcel::readAligned(T *pArg) const {
COMPILE_TIME_ASSERT_FUNCTION_SCOPE(PAD_SIZE(sizeof(T)) == sizeof(T));
if ((mDataPos+sizeof(T)) <= mDataSize) {
const void* data = mData+mDataPos;
mDataPos += sizeof(T);
*pArg = *reinterpret_cast<const T*>(data);
return NO_ERROR;
} else {
return NOT_ENOUGH_DATA;
}
}
template<class T>
T Parcel::readAligned() const {
T result;
if (readAligned(&result) != NO_ERROR) {
result = 0;
}
return result;
}
template<class T>
status_t Parcel::writeAligned(T val) {
COMPILE_TIME_ASSERT_FUNCTION_SCOPE(PAD_SIZE(sizeof(T)) == sizeof(T));
if ((mDataPos+sizeof(val)) <= mDataCapacity) {
restart_write:
*reinterpret_cast<T*>(mData+mDataPos) = val;
return finishWrite(sizeof(val));
}
status_t err = growData(sizeof(val));
if (err == NO_ERROR) goto restart_write;
return err;
}
status_t Parcel::readInt32(int32_t *pArg) const
{
return readAligned(pArg);
}
int32_t Parcel::readInt32() const
{
return readAligned<int32_t>();
}
status_t Parcel::readInt64(int64_t *pArg) const
{
return readAligned(pArg);
}
int64_t Parcel::readInt64() const
{
return readAligned<int64_t>();
}
status_t Parcel::readFloat(float *pArg) const
{
return readAligned(pArg);
}
float Parcel::readFloat() const
{
return readAligned<float>();
}
status_t Parcel::readDouble(double *pArg) const
{
return readAligned(pArg);
}
double Parcel::readDouble() const
{
return readAligned<double>();
}
status_t Parcel::readIntPtr(intptr_t *pArg) const
{
return readAligned(pArg);
}
intptr_t Parcel::readIntPtr() const
{
return readAligned<intptr_t>();
}
const char* Parcel::readCString() const
{
const size_t avail = mDataSize-mDataPos;
if (avail > 0) {
const char* str = reinterpret_cast<const char*>(mData+mDataPos);
// is the string's trailing NUL within the parcel's valid bounds?
const char* eos = reinterpret_cast<const char*>(memchr(str, 0, avail));
if (eos) {
const size_t len = eos - str;
mDataPos += PAD_SIZE(len+1);
LOGV("readCString Setting data pos of %p to %d/n", this, mDataPos);
return str;
}
}
return NULL;
}
String8 Parcel::readString8() const
{
int32_t size = readInt32();
// watch for potential int overflow adding 1 for trailing NUL
if (size > 0 && size < INT32_MAX) {
const char* str = (const char*)readInplace(size+1);
if (str) return String8(str, size);
}
return String8();
}
String16 Parcel::readString16() const
{
size_t len;
const char16_t* str = readString16Inplace(&len);
if (str) return String16(str, len);
LOGE("Reading a NULL string not supported here.");
return String16();
}
const char16_t* Parcel::readString16Inplace(size_t* outLen) const
{
int32_t size = readInt32();
// watch for potential int overflow from size+1
if (size >= 0 && size < INT32_MAX) {
*outLen = size;
const char16_t* str = (const char16_t*)readInplace((size+1)*sizeof(char16_t));
if (str != NULL) {
return str;
}
}
*outLen = 0;
return NULL;
}
sp Parcel::readStrongBinder() const
{
sp val;
unflatten_binder(ProcessState::self(), *this, &val);
return val;
}
wp Parcel::readWeakBinder() const
{
wp val;
unflatten_binder(ProcessState::self(), *this, &val);
return val;
}
native_handle* Parcel::readNativeHandle() const
{
int numFds, numInts;
status_t err;
err = readInt32(&numFds);
if (err != NO_ERROR) return 0;
err = readInt32(&numInts);
if (err != NO_ERROR) return 0;
native_handle* h = native_handle_create(numFds, numInts);
for (int i=0 ; err==NO_ERROR && i<numFds ; i++) {
h->data[i] = dup(readFileDescriptor());
if (h->data[i] < 0) err = BAD_VALUE;
}
err = read(h->data + numFds, sizeof(int)*numInts);
if (err != NO_ERROR) {
native_handle_close(h);
native_handle_delete(h);
h = 0;
}
return h;
}
int Parcel::readFileDescriptor() const
{
const flat_binder_object* flat = readObject(true);
if (flat) {
switch (flat->type) {
case BINDER_TYPE_FD:
//LOGI("Returning file descriptor %ld from parcel %p/n", flat->handle, this);
return flat->handle;
}
}
return BAD_TYPE;
}
status_t Parcel::read(Flattenable& val) const
{
// size
const size_t len = this->readInt32();
const size_t fd_count = this->readInt32();
// payload
void const* buf = this->readInplace(PAD_SIZE(len));
if (buf == NULL)
return BAD_VALUE;
int* fds = NULL;
if (fd_count) {
fds = new int[fd_count];
}
status_t err = NO_ERROR;
for (size_t i=0 ; i<fd_count && err==NO_ERROR ; i++) {
fds[i] = dup(this->readFileDescriptor());
if (fds[i] < 0) err = BAD_VALUE;
}
if (err == NO_ERROR) {
err = val.unflatten(buf, len, fds, fd_count);
}
if (fd_count) {
delete [] fds;
}
return err;
}
const flat_binder_object* Parcel::readObject(bool nullMetaData) const
{
const size_t DPOS = mDataPos;
if ((DPOS+sizeof(flat_binder_object)) <= mDataSize) {
const flat_binder_object* obj
= reinterpret_cast<const flat_binder_object*>(mData+DPOS);
mDataPos = DPOS + sizeof(flat_binder_object);
if (!nullMetaData && (obj->cookie == NULL && obj->binder == NULL)) {
// When transferring a NULL object, we don't write it into
// the object list, so we don't want to check for it when
// reading.
LOGV("readObject Setting data pos of %p to %d/n", this, mDataPos);
return obj;
}
// Ensure that this object is valid...
size_t* const OBJS = mObjects;
const size_t N = mObjectsSize;
size_t opos = mNextObjectHint;
if (N > 0) {
LOGV("Parcel %p looking for obj at %d, hint=%d/n",
this, DPOS, opos);
// Start at the current hint position, looking for an object at
// the current data position.
if (opos < N) {
while (opos < (N-1) && OBJS[opos] < DPOS) {
opos++;
}
} else {
opos = N-1;
}
if (OBJS[opos] == DPOS) {
// Found it!
LOGV("Parcel found obj %d at index %d with forward search",
this, DPOS, opos);
mNextObjectHint = opos+1;
LOGV("readObject Setting data pos of %p to %d/n", this, mDataPos);
return obj;
}
// Look backwards for it...
while (opos > 0 && OBJS[opos] > DPOS) {
opos--;
}
if (OBJS[opos] == DPOS) {
// Found it!
LOGV("Parcel found obj %d at index %d with backward search",
this, DPOS, opos);
mNextObjectHint = opos+1;
LOGV("readObject Setting data pos of %p to %d/n", this, mDataPos);
return obj;
}
}
LOGW("Attempt to read object from Parcel %p at offset %d that is not in the object list",
this, DPOS);
}
return NULL;
}
void Parcel::closeFileDescriptors()
{
size_t i = mObjectsSize;
if (i > 0) {
//LOGI("Closing file descriptors for %d objects...", mObjectsSize);
}
while (i > 0) {
i--;
const flat_binder_object* flat
= reinterpret_cast<flat_binder_object*>(mData+mObjects[i]);
if (flat->type == BINDER_TYPE_FD) {
//LOGI("Closing fd: %ld/n", flat->handle);
close(flat->handle);
}
}
}
const uint8_t* Parcel::ipcData() const
{
return mData;
}
size_t Parcel::ipcDataSize() const
{
return (mDataSize > mDataPos ? mDataSize : mDataPos);
}
const size_t* Parcel::ipcObjects() const
{
return mObjects;
}
size_t Parcel::ipcObjectsCount() const
{
return mObjectsSize;
}
void Parcel::ipcSetDataReference(const uint8_t* data, size_t dataSize,
const size_t* objects, size_t objectsCount, release_func relFunc, void* relCookie)
{
freeDataNoInit();
mError = NO_ERROR;
mData = const_cast<uint8_t*>(data);
mDataSize = mDataCapacity = dataSize;
//LOGI("setDataReference Setting data size of %p to %lu (pid=%d)/n", this, mDataSize, getpid());
mDataPos = 0;
LOGV("setDataReference Setting data pos of %p to %d/n", this, mDataPos);
mObjects = const_cast<size_t*>(objects);
mObjectsSize = mObjectsCapacity = objectsCount;
mNextObjectHint = 0;
mOwner = relFunc;
mOwnerCookie = relCookie;
scanForFds();
}
void Parcel::print(TextOutput& to, uint32_t flags) const
{
to << "Parcel(";
if (errorCheck() != NO_ERROR) {
const status_t err = errorCheck();
to << "Error: " << (void*)err << " /"" << strerror(-err) << "/"";
} else if (dataSize() > 0) {
const uint8_t* DATA = data();
to << indent << HexDump(DATA, dataSize()) << dedent;
const size_t* OBJS = objects();
const size_t N = objectsCount();
for (size_t i=0; i<N; i++) {
const flat_binder_object* flat
= reinterpret_cast<const flat_binder_object*>(DATA+OBJS[i]);
to << endl << "Object #" << i << " @ " << (void*)OBJS[i] << ": "
<< TypeCode(flat->type & 0x7f7f7f00)
<< " = " << flat->binder;
}
} else {
to << "NULL";
}
to << ")";
}
void Parcel::releaseObjects()
{
const sp proc(ProcessState::self());
size_t i = mObjectsSize;
uint8_t* const data = mData;
size_t* const objects = mObjects;
while (i > 0) {
i--;
const flat_binder_object* flat
= reinterpret_cast<flat_binder_object*>(data+objects[i]);
release_object(proc, *flat, this);
}
}
void Parcel::acquireObjects()
{
const sp proc(ProcessState::self());
size_t i = mObjectsSize;
uint8_t* const data = mData;
size_t* const objects = mObjects;
while (i > 0) {
i--;
const flat_binder_object* flat
= reinterpret_cast<flat_binder_object*>(data+objects[i]);
acquire_object(proc, *flat, this);
}
}
void Parcel::freeData()
{
freeDataNoInit();
initState();
}
void Parcel::freeDataNoInit()
{
if (mOwner) {
//LOGI("Freeing data ref of %p (pid=%d)/n", this, getpid());
mOwner(this, mData, mDataSize, mObjects, mObjectsSize, mOwnerCookie);
} else {
releaseObjects();
if (mData) free(mData);
if (mObjects) free(mObjects);
}
}
status_t Parcel::growData(size_t len)
{
size_t newSize = ((mDataSize+len)*3)/2;
return (newSize <= mDataSize)
? (status_t) NO_MEMORY
: continueWrite(newSize);
}
status_t Parcel::restartWrite(size_t desired)
{
if (mOwner) {
freeData();
return continueWrite(desired);
}
uint8_t* data = (uint8_t*)realloc(mData, desired);
if (!data && desired > mDataCapacity) {
mError = NO_MEMORY;
return NO_MEMORY;
}
releaseObjects();
if (data) {
mData = data;
mDataCapacity = desired;
}
mDataSize = mDataPos = 0;
LOGV("restartWrite Setting data size of %p to %d/n", this, mDataSize);
LOGV("restartWrite Setting data pos of %p to %d/n", this, mDataPos);
free(mObjects);
mObjects = NULL;
mObjectsSize = mObjectsCapacity = 0;
mNextObjectHint = 0;
mHasFds = false;
mFdsKnown = true;
return NO_ERROR;
}
status_t Parcel::continueWrite(size_t desired)
{
// If shrinking, first adjust for any objects that appear
// after the new data size.
size_t objectsSize = mObjectsSize;
if (desired < mDataSize) {
if (desired == 0) {
objectsSize = 0;
} else {
while (objectsSize > 0) {
if (mObjects[objectsSize-1] < desired)
break;
objectsSize--;
}
}
}
if (mOwner) {
// If the size is going to zero, just release the owner's data.
if (desired == 0) {
freeData();
return NO_ERROR;
}
// If there is a different owner, we need to take
// posession.
uint8_t* data = (uint8_t*)malloc(desired);
if (!data) {
mError = NO_MEMORY;
return NO_MEMORY;
}
size_t* objects = NULL;
if (objectsSize) {
objects = (size_t*)malloc(objectsSize*sizeof(size_t));
if (!objects) {
mError = NO_MEMORY;
return NO_MEMORY;
}
// Little hack to only acquire references on objects
// we will be keeping.
size_t oldObjectsSize = mObjectsSize;
mObjectsSize = objectsSize;
acquireObjects();
mObjectsSize = oldObjectsSize;
}
if (mData) {
memcpy(data, mData, mDataSize < desired ? mDataSize : desired);
}
if (objects && mObjects) {
memcpy(objects, mObjects, objectsSize*sizeof(size_t));
}
//LOGI("Freeing data ref of %p (pid=%d)/n", this, getpid());
mOwner(this, mData, mDataSize, mObjects, mObjectsSize, mOwnerCookie);
mOwner = NULL;
mData = data;
mObjects = objects;
mDataSize = (mDataSize < desired) ? mDataSize : desired;
LOGV("continueWrite Setting data size of %p to %d/n", this, mDataSize);
mDataCapacity = desired;
mObjectsSize = mObjectsCapacity = objectsSize;
mNextObjectHint = 0;
} else if (mData) {
if (objectsSize < mObjectsSize) {
// Need to release refs on any objects we are dropping.
const sp proc(ProcessState::self());
for (size_t i=objectsSize; i<mObjectsSize; i++) {
const flat_binder_object* flat
= reinterpret_cast<flat_binder_object*>(mData+mObjects[i]);
if (flat->type == BINDER_TYPE_FD) {
// will need to rescan because we may have lopped off the only FDs
mFdsKnown = false;
}
release_object(proc, *flat, this);
}
size_t* objects =
(size_t*)realloc(mObjects, objectsSize*sizeof(size_t));
if (objects) {
mObjects = objects;
}
mObjectsSize = objectsSize;
mNextObjectHint = 0;
}
// We own the data, so we can just do a realloc().
if (desired > mDataCapacity) {
uint8_t* data = (uint8_t*)realloc(mData, desired);
if (data) {
mData = data;
mDataCapacity = desired;
} else if (desired > mDataCapacity) {
mError = NO_MEMORY;
return NO_MEMORY;
}
} else {
mDataSize = desired;
LOGV("continueWrite Setting data size of %p to %d/n", this, mDataSize);
if (mDataPos > desired) {
mDataPos = desired;
LOGV("continueWrite Setting data pos of %p to %d/n", this, mDataPos);
}
}
} else {
// This is the first data. Easy!
uint8_t* data = (uint8_t*)malloc(desired);
if (!data) {
mError = NO_MEMORY;
return NO_MEMORY;
}
if(!(mDataCapacity == 0 && mObjects == NULL
&& mObjectsCapacity == 0)) {
LOGE("continueWrite: %d/%p/%d/%d", mDataCapacity, mObjects, mObjectsCapacity, desired);
}
mData = data;
mDataSize = mDataPos = 0;
LOGV("continueWrite Setting data size of %p to %d/n", this, mDataSize);
LOGV("continueWrite Setting data pos of %p to %d/n", this, mDataPos);
mDataCapacity = desired;
}
return NO_ERROR;
}
void Parcel::initState()
{
mError = NO_ERROR;
mData = 0;
mDataSize = 0;
mDataCapacity = 0;
mDataPos = 0;
LOGV("initState Setting data size of %p to %d/n", this, mDataSize);
LOGV("initState Setting data pos of %p to %d/n", this, mDataPos);
mObjects = NULL;
mObjectsSize = 0;
mObjectsCapacity = 0;
mNextObjectHint = 0;
mHasFds = false;
mFdsKnown = true;
mOwner = NULL;
}
void Parcel::scanForFds() const
{
bool hasFds = false;
for (size_t i=0; i<mObjectsSize; i++) {
const flat_binder_object* flat
= reinterpret_cast<const flat_binder_object*>(mData + mObjects[i]);
if (flat->type == BINDER_TYPE_FD) {
hasFds = true;
break;
}
}
mHasFds = hasFds;
mFdsKnown = true;
}
}; // namespace android

本文的源码使用的是Android 2.1版本。

上一篇中我们透过源码看到了Parcel背后的机制，本质上把它当成一个Serialize就可以了，只是它是在内存中完成的序列化和反序列化，利用的是连续的内存空间，因此会更加高效。

我们接下来要说的是Parcel类如何应用。就应用程序而言，最常见使用Parcel类的场景就是在Activity间传递数据。没错，在Activity间使用Intent传递数据的时候，可以通过Parcelable机制传递复杂的对象。

在下面的程序中，MyColor用于保存一个颜色值，MainActivity在用户点击屏幕时将MyColor对象设成红色，传递到SubActivity中，此时SubActivity的TextView显示为红色的背景；当点击SubActivity时，将颜色值改为绿色，返回MainActivity，期望的是MainActivity的TextView显示绿色背景。

来看一下MyColor类的实现代码：

[java] view plain copy