vm/Sync.h

/*
 * 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.
 */
/*
 * Object synchronization functions.
 */
#ifndef _DALVIK_SYNC
#define _DALVIK_SYNC

#define LW_SHAPE_THIN 0
#define LW_SHAPE_FAT 1
#define LW_SHAPE_MASK 0x1
#define LW_SHAPE(x) ((x) & LW_SHAPE_MASK)

#define LW_HASH_STATE_UNHASHED 0
#define LW_HASH_STATE_HASHED 1
#define LW_HASH_STATE_HASHED_AND_MOVED 2
#define LW_HASH_STATE_MASK 0x3
#define LW_HASH_STATE_SHIFT 1
#define LW_HASH_STATE(x) (((x) >> LW_HASH_STATE_SHIFT) & LW_HASH_STATE_MASK)

#define LW_MONITOR(x) \
  ((Monitor*)((x) & ~((LW_HASH_STATE_MASK << LW_HASH_STATE_SHIFT) | LW_SHAPE_MASK)))

#define LW_LOCK_OWNER_MASK 0xffff
#define LW_LOCK_OWNER_SHIFT 3
#define LW_LOCK_OWNER(x) (((x) >> LW_LOCK_OWNER_SHIFT) & LW_LOCK_OWNER_MASK)

#define LW_LOCK_COUNT_MASK 0x1fff
#define LW_LOCK_COUNT_SHIFT 19
#define LW_LOCK_COUNT(x) (((x) >> LW_LOCK_COUNT_SHIFT) & LW_LOCK_COUNT_MASK)

struct Object;
struct Monitor;
struct Thread;
typedef struct Monitor Monitor;

#define QUIET_ZYGOTE_MONITOR 1

/*
 * Initialize a Lock to the proper starting value.
 * This is necessary for thin locking.
 */
#define DVM_LOCK_INITIAL_THIN_VALUE (0)

#define DVM_LOCK_INIT(lock) \
    do { *(lock) = DVM_LOCK_INITIAL_THIN_VALUE; } while (0)

/*
 * Returns true if the lock has been fattened.
 */
#define IS_LOCK_FAT(lock)   (LW_SHAPE(*(lock)) == LW_SHAPE_FAT)

/*
 * Acquire the object's monitor.
 */
void dvmLockObject(struct Thread* self, struct Object* obj);

/* Returns true if the unlock succeeded.
 * If the unlock failed, an exception will be pending.
 */
bool dvmUnlockObject(struct Thread* self, struct Object* obj);

/*
 * Implementations of some java/lang/Object calls.
 */
void dvmObjectWait(struct Thread* self, struct Object* obj,
    s8 timeout, s4 nanos, bool interruptShouldThrow);
void dvmObjectNotify(struct Thread* self, struct Object* obj);
void dvmObjectNotifyAll(struct Thread* self, struct Object* obj);

/*
 * Implementation of System.identityHashCode().
 */
u4 dvmIdentityHashCode(struct Object* obj);

/*
 * Implementation of Thread.sleep().
 */
void dvmThreadSleep(u8 msec, u4 nsec);

/*
 * Implementation of Thread.interrupt().
 *
 * Interrupt a thread.  If it's waiting on a monitor, wake it up.
 */
void dvmThreadInterrupt(volatile struct Thread* thread);

/* create a new Monitor struct */
Monitor* dvmCreateMonitor(struct Object* obj);

/* free an object's monitor during GC */
void dvmFreeObjectMonitor_internal(u4 *lock);
#define dvmFreeObjectMonitor(obj) \
    do { \
        Object *DFM_obj_ = (obj); \
        if (IS_LOCK_FAT(&DFM_obj_->lock)) { \
            dvmFreeObjectMonitor_internal(&DFM_obj_->lock); \
        } \
    } while (0)

/* free monitor list */
void dvmFreeMonitorList(void);

/*
 * Get the object a monitor is part of.
 *
 * Returns NULL if "mon" is NULL or the monitor is not part of an object
 * (which should only happen for Thread.sleep() in the current implementation).
 */
struct Object* dvmGetMonitorObject(Monitor* mon);

/*
 * Checks whether the object is held by the specified thread.
 */
bool dvmHoldsLock(struct Thread* thread, struct Object* obj);

/*
 * Debug.
 */
void dvmDumpMonitorInfo(const char* msg);

#endif /*_DALVIK_SYNC*/