replicant-frameworks_native/include/binder/IBinder.h
Christopher Tate 71f64dd876 Binder linkage no longer depends on JNI objrefs as persistent tokens
There are two areas that have changed to eliminate the assumption that
local jobject references are both canonical and persistent:

1. JavaBBinderHolder no longer holds onto and reuses it parent object
reference per se.  Since the underlying JavaBBinder object holds a
real global ref, this was redundant anyway.  Now, for purposes of its
transient need to perform JNI operations, it simply uses the current
jobject ref(s) passed during method invocation, and no longer attempts
to hold these refs beyond the scope of a single invocation.

2. Binder obituaries no longer assume that a jobject reference to a
recipient will always compare == as a 32-bit value with any future
reference to the same object.  The implementation now asks Dalvik
whether object references match.

This amended patch fixes the earlier bug around races between
remote binder death cleanup and local explicit unregistration of
VM-side death recipients.

Bug 2090115

Change-Id: I70bd788a80ea953632b1f466f385ab6b78ef2913
2011-02-28 11:37:20 -08:00

160 lines
5.9 KiB
C++

/*
* Copyright (C) 2008 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ANDROID_IBINDER_H
#define ANDROID_IBINDER_H
#include <utils/Errors.h>
#include <utils/RefBase.h>
#include <utils/String16.h>
#include <utils/Vector.h>
#define B_PACK_CHARS(c1, c2, c3, c4) \
((((c1)<<24)) | (((c2)<<16)) | (((c3)<<8)) | (c4))
// ---------------------------------------------------------------------------
namespace android {
class BBinder;
class BpBinder;
class IInterface;
class Parcel;
/**
* Base class and low-level protocol for a remotable object.
* You can derive from this class to create an object for which other
* processes can hold references to it. Communication between processes
* (method calls, property get and set) is down through a low-level
* protocol implemented on top of the transact() API.
*/
class IBinder : public virtual RefBase
{
public:
enum {
FIRST_CALL_TRANSACTION = 0x00000001,
LAST_CALL_TRANSACTION = 0x00ffffff,
PING_TRANSACTION = B_PACK_CHARS('_','P','N','G'),
DUMP_TRANSACTION = B_PACK_CHARS('_','D','M','P'),
INTERFACE_TRANSACTION = B_PACK_CHARS('_', 'N', 'T', 'F'),
// Corresponds to TF_ONE_WAY -- an asynchronous call.
FLAG_ONEWAY = 0x00000001
};
IBinder();
/**
* Check if this IBinder implements the interface named by
* @a descriptor. If it does, the base pointer to it is returned,
* which you can safely static_cast<> to the concrete C++ interface.
*/
virtual sp<IInterface> queryLocalInterface(const String16& descriptor);
/**
* Return the canonical name of the interface provided by this IBinder
* object.
*/
virtual const String16& getInterfaceDescriptor() const = 0;
virtual bool isBinderAlive() const = 0;
virtual status_t pingBinder() = 0;
virtual status_t dump(int fd, const Vector<String16>& args) = 0;
virtual status_t transact( uint32_t code,
const Parcel& data,
Parcel* reply,
uint32_t flags = 0) = 0;
/**
* This method allows you to add data that is transported through
* IPC along with your IBinder pointer. When implementing a Binder
* object, override it to write your desired data in to @a outData.
* You can then call getConstantData() on your IBinder to retrieve
* that data, from any process. You MUST return the number of bytes
* written in to the parcel (including padding).
*/
class DeathRecipient : public virtual RefBase
{
public:
virtual void binderDied(const wp<IBinder>& who) = 0;
};
/**
* Register the @a recipient for a notification if this binder
* goes away. If this binder object unexpectedly goes away
* (typically because its hosting process has been killed),
* then DeathRecipient::binderDied() will be called with a reference
* to this.
*
* The @a cookie is optional -- if non-NULL, it should be a
* memory address that you own (that is, you know it is unique).
*
* @note You will only receive death notifications for remote binders,
* as local binders by definition can't die without you dying as well.
* Trying to use this function on a local binder will result in an
* INVALID_OPERATION code being returned and nothing happening.
*
* @note This link always holds a weak reference to its recipient.
*
* @note You will only receive a weak reference to the dead
* binder. You should not try to promote this to a strong reference.
* (Nor should you need to, as there is nothing useful you can
* directly do with it now that it has passed on.)
*/
virtual status_t linkToDeath(const sp<DeathRecipient>& recipient,
void* cookie = NULL,
uint32_t flags = 0) = 0;
/**
* Remove a previously registered death notification.
* The @a recipient will no longer be called if this object
* dies. The @a cookie is optional. If non-NULL, you can
* supply a NULL @a recipient, and the recipient previously
* added with that cookie will be unlinked.
*/
virtual status_t unlinkToDeath( const wp<DeathRecipient>& recipient,
void* cookie = NULL,
uint32_t flags = 0,
wp<DeathRecipient>* outRecipient = NULL) = 0;
virtual bool checkSubclass(const void* subclassID) const;
typedef void (*object_cleanup_func)(const void* id, void* obj, void* cleanupCookie);
virtual void attachObject( const void* objectID,
void* object,
void* cleanupCookie,
object_cleanup_func func) = 0;
virtual void* findObject(const void* objectID) const = 0;
virtual void detachObject(const void* objectID) = 0;
virtual BBinder* localBinder();
virtual BpBinder* remoteBinder();
protected:
virtual ~IBinder();
private:
};
}; // namespace android
// ---------------------------------------------------------------------------
#endif // ANDROID_IBINDER_H