From ec688b4723a041044226358bcd4dd6e2da39da49 Mon Sep 17 00:00:00 2001 From: Luca Muscariello Date: Thu, 23 Feb 2017 17:01:02 +0100 Subject: Initial commit: cframework. Longbow and Libparc Change-Id: I90378dbd30da6033b20fb1f829b3b822cf366c59 Signed-off-by: Luca Muscariello --- libparc/parc/concurrent/parc_Lock.h | 377 ++++++++++++++++++++++++++++++++++++ 1 file changed, 377 insertions(+) create mode 100755 libparc/parc/concurrent/parc_Lock.h (limited to 'libparc/parc/concurrent/parc_Lock.h') diff --git a/libparc/parc/concurrent/parc_Lock.h b/libparc/parc/concurrent/parc_Lock.h new file mode 100755 index 00000000..ecba1c19 --- /dev/null +++ b/libparc/parc/concurrent/parc_Lock.h @@ -0,0 +1,377 @@ +/* + * Copyright (c) 2017 Cisco and/or its affiliates. + * 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. + */ + +/** + * @file parc_Lock.h + * @ingroup threading + * @brief <#Brief Description#> + * + * <#Detailed Description#> + * + */ +#ifndef PARCLibrary_parc_Lock +#define PARCLibrary_parc_Lock +#include + +#include +#include + +struct PARCLock; +typedef struct PARCLock PARCLock; + +/** + * Increase the number of references to a `PARCLock` instance. + * + * Note that new `PARCLock` is not created, + * only that the given `PARCLock` reference count is incremented. + * Discard the reference by invoking `parcLock_Release`. + * + * @param [in] instance A pointer to a valid PARCLock instance. + * + * @return The same value as @p instance. + * + * Example: + * @code + * { + * PARCLock *a = parcLock_Create(); + * + * PARCLock *b = parcLock_Acquire(); + * + * parcLock_Release(&a); + * parcLock_Release(&b); + * } + * @endcode + */ +PARCLock *parcLock_Acquire(const PARCLock *instance); + +#ifdef PARCLibrary_DISABLE_VALIDATION +# define parcLock_OptionalAssertValid(_instance_) +#else +# define parcLock_OptionalAssertValid(_instance_) parcLock_AssertValid(_instance_) +#endif + +/** + * Assert that the given `PARCLock` instance is valid. + * + * @param [in] instance A pointer to a valid PARCLock instance. + * + * Example: + * @code + * { + * PARCLock *a = parcLock_Create(); + * + * parcLock_AssertValid(a); + * + * printf("Instance is valid.\n"); + * + * parcLock_Release(&b); + * } + * @endcode + */ +void parcLock_AssertValid(const PARCLock *instance); + +/** + * Create an instance of PARCLock + * + * <#Paragraphs Of Explanation#> + * + * @return non-NULL A pointer to a valid PARCLock instance. + * @return NULL An error occurred. + * + * Example: + * @code + * { + * PARCLock *a = parcLock_Create(); + * + * parcLock_Release(&a); + * } + * @endcode + */ +PARCLock *parcLock_Create(void); + +/** + * Compares @p instance with @p other for order. + * + * Returns a negative integer, zero, or a positive integer as @p instance + * is less than, equal to, or greater than @p other. + * + * @param [in] instance A pointer to a valid PARCLock instance. + * @param [in] other A pointer to a valid PARCLock instance. + * + * @return <0 Instance is less than @p other. + * @return 0 Instance a and instance b compare the same. + * @return >0 Instance a is greater than instance b. + * + * Example: + * @code + * { + * PARCLock *a = parcLock_Create(); + * PARCLock *b = parcLock_Create(); + * + * if (parcLock_Compare(a, b) == 0) { + * printf("Instances are equal.\n"); + * } + * + * parcLock_Release(&a); + * parcLock_Release(&b); + * } + * @endcode + * + * @see parcLock_Equals + */ +int parcLock_Compare(const PARCLock *instance, const PARCLock *other); + +/** + * Print a human readable representation of the given `PARCLock`. + * + * @param [in] instance A pointer to a valid PARCLock instance. + * @param [in] indentation The indentation level to use for printing. + * + * Example: + * @code + * { + * PARCLock *a = parcLock_Create(); + * + * parcLock_Display(a, 0); + * + * parcLock_Release(&a); + * } + * @endcode + */ +void parcLock_Display(const PARCLock *instance, int indentation); + +/** + * Determine if an instance of `PARCLock` is valid. + * + * Valid means the internal state of the type is consistent with its required current or future behaviour. + * This may include the validation of internal instances of types. + * + * @param [in] instance A pointer to a valid PARCLock instance. + * + * @return true The instance is valid. + * @return false The instance is not valid. + * + * Example: + * @code + * { + * PARCLock *a = parcLock_Create(); + * + * if (parcLock_IsValid(a)) { + * printf("Instance is valid.\n"); + * } + * + * parcLock_Release(&a); + * } + * @endcode + * + */ +bool parcLock_IsValid(const PARCLock *instance); + +/** + * Release a previously acquired reference to the given `PARCLock` instance, + * decrementing the reference count for the instance. + * + * The pointer to the instance is set to NULL as a side-effect of this function. + * + * If the invocation causes the last reference to the instance to be released, + * the instance is deallocated and the instance's implementation will perform + * additional cleanup and release other privately held references. + * + * @param [in,out] instancePtr A pointer to a pointer to the instance to release. + * + * Example: + * @code + * { + * PARCLock *a = parcLock_Create(); + * + * parcLock_Release(&a); + * } + * @endcode + */ +void parcLock_Release(PARCLock **instancePtr); + +/** + * Append a representation of the specified `PARCLock` instance to the given `PARCBufferComposer`. + * + * @param [in] name A pointer to a `PARCLock` instance whose representation should be appended to the @p composer. + * @param [in,out] composer A pointer to a `PARCBufferComposer` instance to be modified. + * + * @return NULL Cannot allocate memory. + * @return non-NULL The @p composer. + * + * Example: + * @code + * { + * PARCBufferComposer *result = parcBufferComposer_Create(); + * + * parcLock_BuildString(instance, result); + * + * char *string = parcBufferComposer_ToString(result); + * printf("Hello: %s\n", string); + * parcMemory_Deallocate(string); + * + * parcBufferComposer_Release(&result); + * } + * @endcode + */ +PARCBufferComposer *parcLock_BuildString(const PARCLock *name, PARCBufferComposer *composer); + +/** + * Produce a null-terminated string representation of the specified `PARCLock`. + * + * The result must be freed by the caller via {@link parcMemory_Deallocate}. + * + * @param [in] instance A pointer to a valid PARCLock instance. + * + * @return NULL Cannot allocate memory. + * @return non-NULL A pointer to an allocated, null-terminated C string that must be deallocated via {@link parcMemory_Deallocate}. + * + * Example: + * @code + * { + * PARCLock *a = parcLock_Create(); + * + * char *string = parcLock_ToString(a); + * + * parcLock_Release(&a); + * + * parcMemory_Deallocate(&string); + * } + * @endcode + * + * @see parcLock_Display + */ +char *parcLock_ToString(const PARCLock *instance); + +/** + * Obtain the lock on the given `PARCLock` instance. + * + * If the lock is already held by another thread, this function will block. + * If the lock is aleady held by the current thread, this function will return `false`. + * + * Implementors must avoid deadlock by attempting to lock the object a second time within the same calling thread. + * + * @param [in] lock A pointer to a valid `PARCLock` instance. + * + * @return true The lock was obtained successfully. + * @return false The lock is already held by the current thread, or the `PARCLock` is invalid. + * + * Example: + * @code + * { + * if (parcLock_Lock(lock)) { + * + * } + * } + * @endcode + */ +bool parcLock_Lock(PARCLock *lock); + +/** + * Try to obtain the advisory lock on the given `PARCObject` instance. + * + * Once the lock is obtained, the caller must release the lock via `parcObject_Unlock`. + * + * @param [in] lock A pointer to a valid `PARCObject` instance. + * + * @return true The `PARCObject` is locked. + * @return false The `PARCObject` is unlocked. + * + * Example: + * @code + * { + * while (parcLock_TryLock(object)) + * ; + * } + * @endcode + */ +bool parcLock_TryLock(PARCLock *lock); + +/** + * Try to unlock the advisory lock on the given PARCObject instance. + * + * @param [in] lock A pointer to a valid PARCObject instance. + * + * @return true The PARCObject was locked and now is unlocked. + * @return false The PARCObject was not locked and remains unlocked. + * + * Example: + * @code + * { + * parcLock_Unlock(object); + * } + * @endcode + */ +bool parcLock_Unlock(PARCLock *lock); + +/** + * Determine if the advisory lock on the given PARCObject instance is locked. + * + * @param [in] lock A pointer to a valid PARCObject instance. + * + * @return true The PARCObject is locked. + * @return false The PARCObject is unlocked. + * Example: + * @code + * { + * <#example#> + * } + * @endcode + */ +bool parcLock_IsLocked(const PARCLock *lock); + +/** + * Causes the calling thread to wait until either another thread invokes the parcObject_Notify() function on the same object. + * + * The calling thread must own this object's lock. + * The calling thread will release ownership of this lock and wait until another thread invokes `parcObject_Notify` + * on the same object. The original calling thread then re-obtains ownership of the lock and resumes execution. + * + * This function must only be called by a thread that is the owner of this object's lock. + * + * @param [in] lock A pointer to a valid PARCObject instance. + * + * Example: + * @code + * { + * + * parcObject_Wait(object); + * } + * @endcode + */ +void parcLock_Wait(PARCLock *lock); + +/** + * Wakes up a single thread that is waiting on this object (see `parcObject_Wait)`. + * If any threads are waiting on this object, one of them is chosen to be awakened. + * The choice is arbitrary and occurs at the discretion of the underlying implementation. + * + * The awakened thread will not be able to proceed until the current thread relinquishes the lock on this object. + * The awakened thread will compete in the usual manner with any other threads that might be actively + * competing to synchronize on this object; + * for example, the awakened thread enjoys no reliable privilege or disadvantage in being the next thread to lock this object. + * + * @param [in] lock A pointer to a valid `PARCObject` instance. + * + * Example: + * @code + * { + * + * parcObject_Notify(object); + * } + * @endcode + */ +void parcLock_Notify(PARCLock *lock); +#endif -- cgit 1.2.3-korg