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Diffstat (limited to 'libparc/parc/algol/parc_Object.h')
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diff --git a/libparc/parc/algol/parc_Object.h b/libparc/parc/algol/parc_Object.h new file mode 100644 index 00000000..0f3a932b --- /dev/null +++ b/libparc/parc/algol/parc_Object.h @@ -0,0 +1,1504 @@ +/* + * 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_Object.h + * @ingroup memory + * @brief Reference Counted Object Memory + * + * An arbitrary C structure stored in allocated memory with a reference counter. + * + * When a PARC Object is created, via `parcObject_Create`, or `parcObject_Copy` it has reference count of 1. + * + * References to a PARC Object are acquired by calling `parcObject_Acquire` + * and once a reference is no longer needed it is released via parcObject_Release`. + * When the last reference is released, the memory storing the PARC Object is deallocated. + * Any further reference to that object or its memory is undefined. + * + * When creating a PARCObject, the caller may supply an instance of `PARCObjectDescriptor` containing + * configuration information used and pointers to functions that are invoked during the lifecycle of the PARC Object. + * Notable functions that are a finalization cleanup function for an object that will be deallocated, + * a clone function for an object that is being cloned, + * and a string generator for an object that is implementing the `ToString` function. + * Implementors of modules that use PARCObject supply a specification of callback + * functions that implement specific behaviours for interfaces using PARC Object. + * + */ +#ifndef libparc_parc_Object_h +#define libparc_parc_Object_h + +#include <stdint.h> +#include <time.h> + +#include <LongBow/runtime.h> +#include <LongBow/longBow_Compiler.h> + +#include <parc/algol/parc_CMacro.h> +//#include <parc/algol/parc_JSON.h> +//#include <parc/algol/parc_HashCode.h> +#ifdef PARCLibrary_DISABLE_VALIDATION +# define parcObject_OptionalAssertValid(_instance_) +#else +# define parcObject_OptionalAssertValid(_instance_) parcObject_AssertValid(_instance_) +#endif + +//Switch to strong type after subclasses are converted +//typedef struct {int unused;} PARCObject; +typedef void PARCObject; + +#include <stdint.h> +#include <stdbool.h> + +typedef struct PARCObjectDescriptor PARCObjectDescriptor; + +/** + * @define parcObject_DescriptorName(_type) + * + * Compose the token for a subtype specific name for a subtype's `PARCObjectDescriptor` + * which is a parameter to `parcObject_Create`. + * + * For example + * @code + * parcObject_DescriptorName(MyType) + * @endcode + * + * generates the token `MyType_Descriptor` + * + * Implementations should use this macro, rather than hardcode the format in their code. + */ +#define parcObject_DescriptorName(_type) parcCMacro_Cat(_type, _Descriptor) + +/** + * @define parcObjectDescriptor_Declaration(_type_) + * + * Create a declaration of a `PARCObjectDescriptor` implementation. + * To define the actual implementation, use `parcObject_Override` + */ +#define parcObjectDescriptor_Declaration(_type_) const PARCObjectDescriptor parcObject_DescriptorName(_type_) + +/** + * @define parcObject_Declare(_type_) + * + * Create a declaration of a `PARCObject` implementation. + * This causes the corresponding `typedef` to be defined + * and the global PARCObjectDescriptor corresponding to the declared type. + */ +#define parcObject_Declare(_type_) \ + typedef struct _type_ _type_; \ + extern parcObjectDescriptor_Declaration(_type_) + +#include <parc/algol/parc_HashCode.h> +#include <parc/algol/parc_JSON.h> + +/** + * A Function that performs the final cleanup and resource deallocation when + * a PARC Object has no more references. + * + * This is deprecated and will be removed. + * Use `PARCObjectDestructor` + */ +typedef void (PARCObjectDestroy)(PARCObject **); + +/** + * A Function that performs the final cleanup and resource deallocation when + * a PARC Object has no more references. + * + * If the function returns `true` the object is automatically deallocated and destroyed. + * If the function returns `false` the object is not automatically deallocated and destroyed, + * and the responsibility for the object's state and memory are the responsibility of + * the `PARCObjectDestructor` function. + */ +typedef bool (PARCObjectDestructor)(PARCObject **); + +/** + * A Function that releases one reference to the given PARC Object. + * On the final release, where the number of references becomes 0, + * the PARCObjectDestroy function is invoked. + */ +typedef void (PARCObjectRelease)(PARCObject **objectPointer); + +/** + * A function that produces a deep-copy of the given PARC Object instance. + */ +typedef PARCObject *(PARCObjectCopy)(const PARCObject *object); + +/** + * A function that invokes the proper _Equals() function for two PARC Object instances. + */ +typedef bool (PARCObjectEquals)(const PARCObject *objectX, const PARCObject *objectY); + +/** + * A function that invokes the proper _Compare() functions for two PARC Object instances. + */ +typedef int (PARCObjectCompare)(const PARCObject *, const PARCObject *); + +/** + * A function that computes the 32-bit hashcode of the given PARC Object instance. + */ +typedef PARCHashCode (PARCObjectHashCode)(const PARCObject *object); + +/** + * A function that produces a C style nul-terminated string representation of the given PARC Object instance. + */ +typedef char *(PARCObjectToString)(const PARCObject *object); + +/** + * A function that displays a human readable representation of the given PARCObject. + */ +typedef void (PARCObjectDisplay)(const PARCObject *object, const int indentation); + +/** + * A function that generates a JSON representation of the given PARC Object instance. + */ +typedef PARCJSON *(PARCObjectToJSON)(const PARCObject *); + +/** + * Every PARCObject descriptor has a pointer to a `PARCObjectState` + * containing arbitrary data related to all instances sharing the descriptor. + */ +typedef void PARCObjectTypeState; + +/** + * Every PARC Object instance contains a pointer to an instance of this structure defining + * the canonical meta-data for the object. + */ +struct PARCObjectDescriptor { + char name[64]; + PARCObjectDestroy *destroy; + PARCObjectDestructor *destructor; + PARCObjectRelease *release; + PARCObjectCopy *copy; + PARCObjectToString *toString; + PARCObjectEquals *equals; + PARCObjectCompare *compare; + PARCObjectHashCode *hashCode; + PARCObjectToJSON *toJSON; + PARCObjectDisplay *display; + const struct PARCObjectDescriptor *super; + size_t objectSize; + unsigned objectAlignment; + bool isLockable; + PARCObjectTypeState *typeState; +}; + + +/** + * Create an allocated instance of `PARCObjectDescriptor`. + * + * @param [in] name A nul-terminated, C string containing the name of the object descriptor. + * @param [in] objectSize The number of bytes necessary to contain the object. + * @param [in] objectAlignment The alignment boundary necessary for the object, a power of 2 greater than or equal to `sizeof(void *)` + * @param [in] isLockable True, if this object implementation supports locking. + * @param [in] destructor The callback function to call when the last `parcObject_Release()` is invoked (replaces @p destroy). + * @param [in] release The callback function to call when `parcObject_Release()` is invoked. + * @param [in] copy The callback function to call when parcObject_Copy() is invoked. + * @param [in] toString The callback function to call when `parcObject_ToString()` is invoked. + * @param [in] equals The callback function to call when `parcObject_Equals()` is invoked. + * @param [in] compare The callback function to call when `parcObject_Compare()` is invoked. + * @param [in] hashCode The callback function to call when `parcObject_HashCode()` is invoked. + * @param [in] toJSON The callback function to call when `parcObject_ToJSON()` is invoked. + * @param [in] display The callback function to call when `parcObject_Display()` is invoked. + * @param [in] super A pointer to a `PARCObjectDescriptor` for the supertype of created `PARCObjectDescriptor` + * @param [in] typeState A pointer to a `PARCObjectTypeState` for the per-type data for the created `PARCObjectDescriptor` + * + * @return NULL Memory could not be allocated to store the `PARCObjectDescriptor` instance. + * @return non-NULL Successfully created the implementation + */ +PARCObjectDescriptor *parcObjectDescriptor_Create(const char *name, + size_t objectSize, + unsigned int objectAlignment, + bool isLockable, + PARCObjectDestructor *destructor, + PARCObjectRelease *release, + PARCObjectCopy *copy, + PARCObjectToString *toString, + PARCObjectEquals *equals, + PARCObjectCompare *compare, + PARCObjectHashCode *hashCode, + PARCObjectToJSON *toJSON, + PARCObjectDisplay *display, + const PARCObjectDescriptor *superType, + PARCObjectTypeState *typeState); + +PARCObjectDescriptor *parcObjectDescriptor_CreateExtension(const PARCObjectDescriptor *superType, const char *name); + +PARCObjectTypeState *parcObjectDescriptor_GetTypeState(const PARCObjectDescriptor *descriptor); + +const PARCObjectDescriptor *parcObjectDescriptor_GetSuperType(const PARCObjectDescriptor *descriptor); + +bool parcObjectDescriptor_Destroy(PARCObjectDescriptor **descriptorPointer); + +/** + * The globally available `PARCObject` descriptor. + */ +extern parcObjectDescriptor_Declaration(PARCObject); + +typedef uint64_t PARCReferenceCount; + +/** + * Assert that an instance of PARC Object is valid. + * + * If the instance is not valid, terminate via an assertion. + * + * 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] object A pointer to a PARC Object instance. + */ +void parcObject_AssertValid(const PARCObject *object); + +/** + * Determine if an instance of PARCObject is valid. + * + * A valid PARCObject has non-NULL, it has a reference count > 0, + * it is non-zero in length, and has a valid alignment. + * + * @param [in] object A pointer to a PARC Object instance. + * + * @return true The PARCObject is valid. + * @return true The PARCObject is invalid. + */ +bool parcObject_IsValid(const PARCObject *object); + +/** + * Create a new reference counted object that is a deep copy of the specified object, + * if possible, or, otherwise, a shallow copy of the object's total allocation memory. + * + * The reference count for the new object is 1. + * + * @param [in] object A pointer to the original object. + * + * @return NULL Memory could not be allocated. + * @return non-NULL A pointer to a new reference counted object. + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * struct MyType *copy = parcObject_Copy(t); + * } + * @endcode + * + * @see parcObject_Release + */ +PARCObject *parcObject_Copy(const PARCObject *object); + +/** + * Compare two object instances. + * + * The comparison function in the first `PARCObjectDescriptor` parameter is used for comparison. + * The objects are expected to be of the same type. Thus, if the comparison function + * associated with the first `PARCObjectDescriptor` function is NULL, it is assumed the + * same holds for the second parameter. In this case, the instance pointers are compared. + * + * @param [in] x An object. + * @param [in] y An object. + * + * @return int The result of the comparison. + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * int compareResult = parcObject_Compare(t, t); + * printf("0? %d\n", compareResult); + * + * parcObject_Release(&t); + * } + * @endcode + */ +int parcObject_Compare(const PARCObject *x, const PARCObject *y); + +/** + * Determine if two PARCObject instances are equal. + * + * Two PARCObject instances are equal if, and only if, the instance pointers are equal. + * + * The following equivalence relations on non-null `PARCObject` instances are maintained: + * + * * It is reflexive: for any non-null reference value x, `PARCObject_Equals(x, x)` + * must return true. + * + * * It is symmetric: for any non-null reference values x and y, + * `parcObject_Equals(x, y)` must return true if and only if + * `parcObject_Equals(y, x)` returns true. + * + * * It is transitive: for any non-null reference values x, y, and z, if + * `parcObject_Equals(x, y)` returns true and + * `parcObject_Equals(y, z)` returns true, + * then `parcObject_Equals(x, z)` must return true. + * + * * It is consistent: for any non-null reference values x and y, multiple + * invocations of `parcObject_Equals(x, y)` consistently return true or + * consistently return false. + * + * * For any non-null reference value x, `parcObject_Equals(x, NULL)` must + * return false. + * + * @param x A pointer to a `PARCObject` instance. + * @param y A pointer to a `PARCObject` instance. + * @return true if the two `PARCObject` instances are equal. + * + * Example: + * @code + * { + * struct MyType *a = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * struct MyType *b = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * if (parcObject_Equals(a, b)) { + * // true + * } else { + * // false + * } + * } + * @endcode + */ +bool parcObject_Equals(const PARCObject *x, const PARCObject *y); + +/** + * Retrieve the hashcode of the given object. + * + * If no object implementation is provided, the hashcode is the 32-bit address + * of the base object pointer. Otherwise, the hashcode is computed by the + * provided hashcode function. + * + * @param [in] object An object. + * + * @return uint32_t The object hashcode + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * PARCHashCode hashcode = parcObject_HashCode(t); + * printf("Hashcode = %" PRIXPARCHashCode "\n", hashcode); + * + * parcObject_Release(&t); + * } + * @endcode + */ +PARCHashCode parcObject_HashCode(const PARCObject *object); + +/** + * Create a C string containing a human readable representation of the given object. + * + * @param [in] object The object from which a string representation will be generated. + * + * @return NULL Memory could not be allocated to contain the C string. + * @return non-NULL An allocated C string that must be deallocated via parcMemory_Deallocate(). + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * char *string = parcObject_ToString(t); + * printf("%s\n", string); + * parcMemory_Deallocate((void **) &string); + * + * parcObject_Release(&t); + * } + * @endcode + */ +char *parcObject_ToString(const PARCObject *object); + +/** + * Create a `PARCJSON` instance (representation) of the given object. + * + * @param [in] object The object from which a JSON instance will be generated. + * + * @return NULL Memory could not be allocated to contain the `PARCJSON` instance. + * @return non-NULL An allocated C string that must be deallocated via parcMemory_Deallocate(). + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * PARCJSON *json = parcObject_ToJSON(t); + * printf("JSON representation: %s\n", parcJSON_ToString(json)); + * parcJSON_Release(&json); + * + * parcObject_Release(&t); + * } + * @endcode + */ +PARCJSON *parcObject_ToJSON(const PARCObject *object); + +/** + * Acquire a new reference to an object. + * + * The reference count to the object is incremented. + * + * @param [in] object The object to which to refer. + * + * @return The same value as the input parameter @p object + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * struct MyType *new = parcObject_Acquire(t); + * + * parcObject_Release(&t); + * parcObject_Release(&new); + * } + * @endcode + */ +PARCObject *parcObject_Acquire(const PARCObject *object); + +/** + * Release a previously acquired reference to the specified 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 an invocation of `parcObject_Release` causes the last reference to + * the instance to be released, it calls the instance's `destructor` function + * specified in the `PARCObjectDescriptor` structure supplied when the instance + * was created (see `parcObject_Create`. + * + * The contents of the deallocated memory used for the PARC object are undefined. + * Do not reference the object after the last release. + * + * @param [in] objectPointer A pointer to a pointer to the instance to release. + * + * @return The number of remaining references to the object. + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * parcObject_Release(&t); + * } + * @endcode + * + * @see parcObject_Create + * @see parcObject_Acquire + */ +PARCReferenceCount parcObject_Release(PARCObject **objectPointer); + +/** + * Get the current `PARCReferenceCount` for the specified object. + * + * The reference count must always be greater than zero. + * + * @param [in] object A pointer to a valid `PARCObject` instance. + * + * @return The current reference count for the specified object. + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * PARCReferenceCount count = parcObject_GetReferenceCount(t); + * + * parcObject_Release(&t); + * } + * @endcode + * + * @see parcObject_Acquire + * @see parcObject_Release + */ +PARCReferenceCount parcObject_GetReferenceCount(const PARCObject *object); + +/** + * Print a human readable representation of the given `PARC Object. + * + * @param [in] object A pointer to the instance to display. + * @param [in] indentation The level of indentation to use to pretty-print the output. + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * parcObject_Display(t, 0); + * + * parcObject_Release(&t); + * } + * @endcode + */ +void parcObject_Display(const PARCObject *object, const int indentation); + +/** + * Get the `PARCObjectDescriptor` of the given `PARCObject`. + * + * @param [in] object A pointer to a valid `PARCObject` instance + * + * @return A pointer to the given PARCObject's `PARCObjectDescriptor`. + * + * Example: + * @code + * { + * struct MyType *t = parcObject_Create(sizeof(struct MyType), &MyType_Descriptor); + * + * PARCObjectDescriptor *descriptor = parcObject_GetDescriptor(t); + * + * parcObject_Release(&t); + * } + * @endcode + */ +const PARCObjectDescriptor *parcObject_GetDescriptor(const PARCObject *object); + +/** + * Set the `PARCObjectDescriptor` of the given `PARCObject`. + * + * @param [in] object A pointer to a valid `PARCObject` instance + * @param [in] objectType A pointer to a valid `PARCObjectDescriptor` instance + * + * @return The previous value of the given PARCObject's `PARCObjectDescriptor`. + */ +const PARCObjectDescriptor *parcObject_SetDescriptor(PARCObject *object, const PARCObjectDescriptor *objectType); + +/** + * @def parcObject_MetaInitialize + * @deprecated Use parcObject_Override instead; + * + * Initialize a PARCObjectDescriptor structure. Every function pointer is set to NULL. + * + * @param [in] objectType A pointer to the PARCObjectDescriptor structure to initialize. + * + * @return The pointer to the initialized PARCObjectDescriptor. + */ +#define parcObject_MetaInitialize(objectType) \ + (objectType)->destructor = NULL, \ + (objectType)->destroy = NULL, \ + (objectType)->release = NULL, \ + (objectType)->copy = NULL, \ + (objectType)->toString = NULL, \ + (objectType)->equals = NULL, \ + (objectType)->compare = NULL, \ + (objectType)->hashCode = NULL, \ + (objectType)->toJSON = NULL, \ + (objectType)->display = NULL, \ + (objectType)->super = NULL + + +/** + * Create new `PARCObjectDescriptor` based on an existing `PARCObjectDescriptor.` + * The new `PARCObjectDescriptor` uses the existing `PARCObjectDescriptor` as the super-type of the new descriptor. + */ +#define parcObject_Extends(_subtype, _superType, ...) \ + LongBowCompiler_IgnoreInitializerOverrides \ + parcObjectDescriptor_Declaration(_subtype) = { \ + .super = &parcObject_DescriptorName(_superType), \ + .name = #_subtype, \ + .objectSize = 0, \ + .objectAlignment = 0, \ + .destroy = NULL, \ + .destructor = NULL, \ + .release = NULL, \ + .copy = NULL, \ + .toString = NULL, \ + .equals = NULL, \ + .compare = NULL, \ + .hashCode = NULL, \ + .toJSON = NULL, \ + .display = NULL, \ + .isLockable = true, \ + .typeState = NULL, \ + __VA_ARGS__ \ + }; \ + LongBowCompiler_WarnInitializerOverrides \ + const PARCObjectDescriptor parcObject_DescriptorName(_subtype) + +/** + * Define a new PARC Object implementation, by composing a new PARC Object Descriptor referencing an old one. + * The new PARC Object implementation must be accompanied by the corresponding `typedef` of the type containing the object's data. + */ +#define parcObject_Override(_subtype, _superType, ...) \ + parcObject_Extends(_subtype, _superType, \ + .objectSize = sizeof(_subtype), \ + .objectAlignment = sizeof(void *), \ + __VA_ARGS__) + + +/// Helper MACROS for PARCObject Normalization +/** \cond */ +/** + * parcObject_DestroyWrapper builds the boiler plate wrapper for PARCObject type conversion in the + * destroy operation. Intended for internal use. + */ +#define parcObject_DestroyWrapper(_type, _fname) \ + static void _autowrap_destroy_ ## _type(PARCObject **object) \ + { \ + _fname((_type **) object); \ + } + +/** + * parcObject_DestructorWrapper builds the boiler plate wrapper for PARCObject type conversion in the + * destroy operation. Intended for internal use. + */ +#define parcObject_DestructorWrapper(_type, _fname) \ + static bool _autowrap_destructor_ ## _type(PARCObject **object) \ + { \ + return _fname((_type **) object); \ + } + +/** + * `parcObject_CopyWrapper` builds the boiler plate wrapper for PARCObject type conversion in the + * copy operation. Intended for internal use. + */ +#define parcObject_CopyWrapper(_type, _fname) \ + static PARCObject *_autowrap_copy_ ## _type(const PARCObject *object) \ + { \ + return (PARCObject *) _fname((const _type *) object); \ + } + +/** + * parcObject_ToStringWrapper builds the boiler plate wrapper for PARCObject type conversion in the + * ToString operation. Intended for internal use. + */ +#define parcObject_ToStringWrapper(_type, _fname) \ + static char *_autowrap_toString_ ## _type(const PARCObject *object) \ + { \ + return _fname((const _type *) object); \ + } + +/** + * `parcObject_EqualsWrapper` builds the boiler plate wrapper for PARCObject type conversion in the + * equals operation. Intended for internal use. + */ +#define parcObject_EqualsWrapper(_type, _fname) \ + static bool _autowrap_equals_ ## _type(const PARCObject *a, const PARCObject *b) \ + { \ + return _fname((const _type *) a, (const _type *) b); \ + } + +/** + * parcObject_CompareWrapper builds the boiler plate wrapper for PARCObject type conversion in the + * compare operation. Intended for internal use. + */ +#define parcObject_CompareWrapper(_type, _fname) \ + static int _autowrap_compare_ ## _type(const PARCObject *a, const PARCObject *b) \ + { \ + return _fname((const _type *) a, (const _type *) b); \ + } + +/** + * `parcObject_HashCodeWrapper` builds the boiler plate wrapper for PARCObject type conversion in the + * HashCode operation. Intended for internal use. + */ +#define parcObject_HashCodeWrapper(_type, _fname) \ + static PARCHashCode _autowrap_hashCode_ ## _type(const PARCObject *object) \ + { \ + return _fname((const _type *) object); \ + } + +/** + * `parcObject_CopyWrapper` builds the boiler plate wrapper for PARCObject type conversion in the + * ToJSON operation. Intended for internal use. + */ +#define parcObject_ToJSONWrapper(_type, _fname) \ + static PARCJSON *_autowrap_toJSON_ ## _type(const PARCObject *object) \ + { \ + return _fname((const _type *) object); \ + } + +/** + * `parcObject_DisplayWrapper` builds the boiler plate wrapper for PARCObject type conversion in the + * Display operation. Intended for internal use. + */ +#define parcObject_DisplayWrapper(_type, _fname) \ + static void _autowrap_Display_ ## _type(const PARCObject *object, const int indentation) \ + { \ + _fname((const _type *) object, indentation); \ + } + +/** + * _autowrap_NULL is a part of the c-macro trick for implement a macro If-Else switch. + * If included as a macro parameter it inserts a comma into the parameter list for that macro. + * This can be used by a switching macro that always resolves to the nth element and the + * presence of a comma generating macro changes which element is the nth. When NULL is used + * as a parameter in a call to "ExtendPARCObject", _autowrap_NULL will be the name generated which + * expands to a comma. + */ +#define _autowrap_NULL(...) , + +/** \endcond */ + + +/** + * @define parcObject_ExtendPARCObject + * @deprecated Use parcObject_Override instead; + * + * @discussion parcObject_ExtendPARCObject is a helper macro for constructing a PARCObjectDescriptor Structure of + * function pointers pointing to a subtype's overriding functions. This struct serves the same + * purpose as a vTable in c++ and provides for simple polymorphism. The functions used as parameters + * should NOT call through to the parcObject function they override as this will result in an infinite loop. + * NULL should be used for functions where PARCObject's default implementation is desired. + * + * Note: It uses the parcCMacro_IfElse trickery to handle NULL parameters. + * + * @param [in] _destroy A pointer to the Destroy callback function. + * @param [in] _copy A pointer to the Copy callback function. + * @param [in] _toString A pointer to the ToString callback function. + * @param [in] _equals A pointer to the Equals callback function. + * @param [in] _compare A pointer to the Compare callback function. + * @param [in] _hashCode A pointer to the HashCode callback function. + * @param [in] _toJSON A pointer to the ToJSON callback function. + */ +#define parcObject_ExtendPARCObject(_type, _destroy, _copy, _toString, _equals, _compare, _hashCode, _toJSON) \ + parcCMacro_IfElse(, parcObject_DestroyWrapper(_type, _destroy), _autowrap_ ## _destroy()) \ + parcCMacro_IfElse(, parcObject_CopyWrapper(_type, _copy), _autowrap_ ## _copy()) \ + parcCMacro_IfElse(, parcObject_ToStringWrapper(_type, _toString), _autowrap_ ## _toString()) \ + parcCMacro_IfElse(, parcObject_EqualsWrapper(_type, _equals), _autowrap_ ## _equals()) \ + parcCMacro_IfElse(, parcObject_CompareWrapper(_type, _compare), _autowrap_ ## _compare()) \ + parcCMacro_IfElse(, parcObject_HashCodeWrapper(_type, _hashCode), _autowrap_ ## _hashCode()) \ + parcCMacro_IfElse(, parcObject_ToJSONWrapper(_type, _toJSON), _autowrap_ ## _toJSON()) \ + parcObject_Override(_type, PARCObject, \ + .destroy = parcCMacro_IfElse(NULL, _autowrap_destroy_ ## _type, _autowrap_ ## _destroy()), \ + .destructor = NULL, \ + .release = NULL, \ + .copy = parcCMacro_IfElse(NULL, _autowrap_copy_ ## _type, _autowrap_ ## _copy()), \ + .toString = parcCMacro_IfElse(NULL, _autowrap_toString_ ## _type, _autowrap_ ## _toString()), \ + .equals = parcCMacro_IfElse(NULL, _autowrap_equals_ ## _type, _autowrap_ ## _equals()), \ + .compare = parcCMacro_IfElse(NULL, _autowrap_compare_ ## _type, _autowrap_ ## _compare()), \ + .hashCode = parcCMacro_IfElse(NULL, _autowrap_hashCode_ ## _type, _autowrap_ ## _hashCode()), \ + .toJSON = parcCMacro_IfElse(NULL, _autowrap_toJSON_ ## _type, _autowrap_ ## _toJSON()), \ + .display = NULL) + +/** + * @define parcObject_CreateInstance + * + * `parcObject_CreateInstance` is a helper C-macro that creates an instance of a PARCObject subtype + * using `parcObject_CreateInstanceImpl` that is based on the PARCObjectDescriptor. + * + * @param [in] _subtype A subtype's type string (e.g. PARCBuffer) + */ +#define parcObject_CreateInstance(_subtype) \ + parcObject_CreateInstanceImpl(&parcObject_DescriptorName(_subtype)) + +PARCObject *parcObject_CreateInstanceImpl(const PARCObjectDescriptor *descriptor); + +/** + * @define parcObject_CreateAndClearInstance + * + * parcObject_CreateAndClearInstance is a helper C-macro that creates an instance of a PARCObject subtype + * using parcObject_CreateAndClear that is based on the PARCObjectDescriptor struct created by the + * parcObject_ExtendPARCObject macro. + * + * @param [in] _subtype A subtype's type string (e.g. PARCBuffer) + */ +#define parcObject_CreateAndClearInstance(_subtype) \ + (_subtype *) parcObject_CreateAndClearInstanceImpl(&parcObject_DescriptorName(_subtype)) + +/** + * Create a reference counted segment of memory of at least @p objectLength long. + * + * The implementation pointer, is either NULL or points to a valid `PARCObjectDescriptor` structure + * containing the callback functions that implement the object's life-cycle operations. + * + * The allocated memory is such that the memory's base address is aligned on a sizeof(void *) boundary, + * and filled with zero bytes. + * + * If memory cannot be allocated, `errno` is set to ENOMEM. + * + * @param [in] descriptor A pointer to a valid `PARCObjectDescriptor` structure. + * + * @return NULL The memory could not be allocated. + * @return non-NULL A pointer to reference counted memory of at least length bytes. + * + * Example: + * @code + * { + * struct timeval *t = parcObject_CreateAndClearInstanceImpl(sizeof(struct timeval), &PARCObject_Descriptor); + * } + * @endcode + * + * @see PARCObjectDescriptor + * @see parcObject_Create + */ +PARCObject *parcObject_CreateAndClearInstanceImpl(const PARCObjectDescriptor *descriptor); + +/** + * Define a static PARCObject instance for the given type, alignment, per-object data. + * + * Once the instance has been defined, it must be initialised via `parcObject_InitInstance` + * or `parcObject_InitAndClearInstance` before it is used. + * + * @return A pointer to an invalid `PARCObject` instance that must be initialised . + */ +#define parcObject_Instance(_type_, _alignment_, _size_) \ + (_type_ *) (& (char[parcObject_TotalSize(_alignment_, _size_)]) { 0 }[parcObject_PrefixLength(sizeof(void *))]) + +/** + * @define parcObject_InitInstance + * + * `parcObject_InitInstance` is a helper C-macro that initializes a portion of memory to contain a `PARCObject` subtype + * using `parcObject_InitInstanceImpl`. + * + * @param [in] _object_ A pointer to memory that will contain the object and its meta-data. + * @param [in] _subtype A subtype's type name. + */ +#define parcObject_InitInstance(_object_, _subtype) \ + parcObject_InitInstanceImpl(_object_, &parcObject_DescriptorName(_subtype)) + +/** + * @define parcObject_InitInstanceImpl + * + * Initialize a PARCObject instance given the `PARCObjectDescriptor`. + * Any previous state of the given PARCObject is destroyed. + * + * @param [in] object A pointer to an existing valid or invalid `PARCObject` instance. + * @param [in] descriptor A pointer to a valid `PARCObjectDescriptor` structure. + */ +PARCObject *parcObject_InitInstanceImpl(PARCObject *object, const PARCObjectDescriptor *descriptor); + +/** + * @define parcObject_InitAndClearInstance + * + * `parcObject_InitAndClearInstance` is a helper C-macro that initializes a portion of memory to contain a PARCObject subtype + * using `parcObject_InitAndClearInstanceImpl`. + * + * @param [in] _object_ A pointer to memory that will contain the object and its meta-data. + * @param [in] _subtype A subtype's type name. + */ +#define parcObject_InitAndClearInstance(_object_, _subtype) \ + parcObject_InitAndClearInstanceImpl(_object_, &parcObject_DescriptorName(_subtype)) + +/** + * Create a reference counted segment of memory of at least @p objectLength long. + * + * The implementation pointer, is either NULL or points to a valid `PARCObjectDescriptor` structure + * containing the callback functions that implement the object's life-cycle operations. + * + * The allocated memory is such that the memory's base address is aligned on a sizeof(void *) boundary, + * and filled with zero bytes. + * + * If memory cannot be allocated, `errno` is set to `ENOMEM`. + * + * @param [in] object A pointer to an existing valid or invalid `PARCObject` instance. + * @param [in] descriptor A pointer to a valid `PARCObjectDescriptor` structure. + * + * @return NULL The memory could not be allocated. + * @return non-NULL A pointer to reference counted memory of at least length bytes. + * + * Example: + * @code + * { + * + * } + * @endcode + * + * @see PARCObjectDescriptor + * @see parcObject_Create + */ +PARCObject *parcObject_InitAndClearInstanceImpl(PARCObject *object, const PARCObjectDescriptor *descriptor); + +/** + * Compute the number of bytes necessary for a PARC Object prefix. + * + * The @p _alignment_ parameter specifies the required memory alignment of the object. + * + * @param [in] _alignment_ An unsigned integer value greater than `sizeof(void *)` + * + * @return The number of bytes necessary for a PARC Object header. + * + * Example: + * @code + * { + * <#example#> + * } + * @endcode + */ +// The constant value here must be greater than or equal to the size of the internal _PARCObjectHeader structure. +#define parcObject_PrefixLength(_alignment_) ((152 + (_alignment_ - 1)) & - _alignment_) + +/** + * Compute the number of bytes necessary for a PARC Object. + * + * The number of bytes consists of the number of bytes for the PARC Object header, padding, and the object's specific data. + * + * The @p _alignment_ parameter specifies the required memory alignment of the object. + * The @p _size_ parameter specifies the number of bytes necessary for the object specific data. + */ +#define parcObject_TotalSize(_alignment_, _size_) (parcObject_PrefixLength(_alignment_) + _size_) + +/** + * Wrap a static, unallocated region of memory producing a valid pointer to a `PARCObject` instance. + * + * Note that the return value will not be equal to the value of @p origin. + * + * @param [in] memory A pointer to memory that will contain the object and its state. + * @param [in] descriptor The subtype name that will be used to compose the name of the `PARCObjectDescriptor` for the object. + * + * @return NULL An error occured. + * + * Example: + * @code + * { + * <#example#> + * } + * @endcode + */ +#define parcObject_Wrap(_memory_, _subtype) \ + parcObject_WrapImpl(_memory_, &parcObject_DescriptorName(_subtype)) + +/** + * Wrap a static, unallocated region of memory producing a valid pointer to a `PARCObject` instance. + * + * Note that the return value will not be equal to the value of @p origin. + * + * @param [in] memory A pointer to memory that will contain the object and its state. + * @param [in] descriptor A pointer to a valid `PARCObjectDescriptor` for the object. + * + * @return NULL An error occured. + * + * Example: + * @code + * { + * <#example#> + * } + * @endcode + */ +PARCObject *parcObject_WrapImpl(void *memory, const PARCObjectDescriptor *descriptor); + +/** + * @def parcObject_ImplementAcquire + * + * `parcObject_ImplementAcquire` is a helper C-macro that creates a canonical subtype specific + * Acquire function. + * + * @param [in] _namespace A subtype's namespace string (e.g. parcBuffer) + * @param [in] _type A subtype's type string (e.g. PARCBuffer) + */ +#define parcObject_ImplementAcquire(_namespace, _type) \ + _type * _namespace ## _Acquire(const _type * pObject) { \ + return (_type *) parcObject_Acquire((PARCObject *) pObject); \ + } extern _type *_namespace ## _Acquire(const _type * pObject) + +/** + * @def parcObject_ImplementRelease + * + * `parcObject_ImplementRelease` is a helper C-macro that creates a canonical subtype specific + * Release function. + * + * @param [in] _namespace A subtype's namespace string (e.g. parcBuffer) + * @param [in] _type A subtype's type string (e.g. PARCBuffer) + */ +#define parcObject_ImplementRelease(_namespace, _type) \ + inline void _namespace ## _Release(_type **pObject) { \ + parcObject_Release((PARCObject **) pObject); \ + } extern void _namespace ## _Release(_type **pObject) + +/** + * `parcObject_ImplementationCheck` is a helper macro that will generate compile time warnings for + * missing canonical functions or canonical functions with faulty signatures. + * + * @param _namespace A subtype's namespace string (e.g. parcBuffer) + * @param _type A subtype's type string (e.g. PARCBuffer) + */ +#define parcObject_ImplementationCheck(_namespace, _type) \ + static void \ + _impl_check() { \ + _type *po; \ + const _type co; \ + const _type *pco; \ + pco = _namespace ## _Copy(&co); \ + pco = _namespace ## _Acquire(&co); \ + pco = pco; \ + _namespace ## _Release(&po); \ + bool b = _namespace ## _Equals(&co, &co); \ + b = b; \ + int i = _namespace ## _Compare(&co, &co); \ + i = i; \ + char *pc = _namespace ## _ToString(&co); \ + pc = pc; \ + uint32_t ui = _namespace ## _HashCode(&co); \ + ui = ui; \ + PARCJSON *pj = _namespace ## _ToJSON(&co); \ + pj = pj; \ + } typedef void parcCMacro_Cat (_type, _IC_NOOP) + +/** + * Obtain the lock on the given `PARCObject` 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] object A pointer to a valid `PARCObject` instance. + * + * @return true The lock was obtained successfully. + * @return false The lock is already held by the current thread, the `PARCObject` is invalid, or does not support locking. + * + * Example: + * @code + * { + * if (parcObject_Lock(object)) { + * + * } + * } + * @endcode + */ +bool parcObject_Lock(const PARCObject *object); + +/** + * @def parcObject_ImplementLock + * + * `parcObject_ImplementLock` is a helper C-macro that defines a static, inline facade for the `parcObject_Lock` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type string (e.g. `PARCBuffer`) + */ +#define parcObject_ImplementLock(_namespace, _type) \ + static inline bool _namespace ## _Lock(const _type * pObject) { \ + return parcObject_Lock((PARCObject *) pObject); \ + } typedef void parcCMacro_Cat (_type, _Lock_NOOP) + +/** + * 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] object A pointer to a valid `PARCObject` instance. + * + * @return true The `PARCObject` is locked. + * @return false The `PARCObject` is unlocked, or does not support locking. + * + * Example: + * @code + * { + * while (parcObject_TryLock(object)) + * ; + * } + * @endcode + */ +bool parcObject_TryLock(const PARCObject *object); + +/** + * @def parcObject_ImplementTryLock + * + * `parcObject_ImplementTryLock` is a helper C-macro that defines a static, inline facade for the `parcObject_TryLock` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type string (e.g. `PARCBuffer`) + */ +#define parcObject_ImplementTryLock(_namespace, _type) \ + static inline bool _namespace ## _TryLock(const _type * pObject) { \ + return parcObject_TryLock((PARCObject *) pObject); \ + } typedef void parcCMacro_Cat (_type, _TryLock_NOOP) + +/** + * Try to unlock the advisory lock on the given `PARCObject` instance. + * + * @param [in] object 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 + * { + * if (parcObject_Lock(Object)) { + * parcObject_Unlock(object); + * } + * } + * @endcode + */ +bool parcObject_Unlock(const PARCObject *object); + +/** + * @def parcObject_ImplementUnlock + * + * `parcObject_ImplementUnlock` is a helper C-macro that defines a static, inline facade for the `parcObject_Unlock` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type string (e.g. `PARCBuffer`) + */ +#define parcObject_ImplementUnlock(_namespace, _type) \ + static inline bool _namespace ## _Unlock(const _type * pObject) { \ + return parcObject_Unlock((PARCObject *) pObject); \ + } typedef void parcCMacro_Cat (_type, _Unlock_NOOP) + +/** + * Determine if the advisory lock on the given PARCObject instance is locked. + * + * @param [in] object A pointer to a valid PARCObject instance. + * + * @return true The `PARCObject` is locked. + * @return false The `PARCObject` is unlocked. + * Example: + * @code + * { + * if (parcObject_Lock(object)) { + * ... + * if (parcObject_IsLocked(object) { + * .... + * } + * ... + * parcObject_Unlock(object); + * } + * } + * @endcode + */ +bool parcObject_IsLocked(const PARCObject *object); + +/** + * @def parcObject_ImplementIsLocked + * + * parcObject_ImplementIsLocked is a helper C-macro that defines a static, inline facade for the `parcObject_IsLocked` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type string (e.g. `PARCBuffer`) + */ +#define parcObject_ImplementIsLocked(_namespace, _type) \ + static inline bool _namespace ## _IsLocked(const _type * pObject) { \ + return parcObject_IsLocked((const PARCObject *) pObject); \ + } typedef void parcCMacro_Cat (_type, _IsLocked_NOOP) + +/** + * Causes the calling thread to wait until 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] object A pointer to a valid PARCObject instance. + * + * Example: + * @code + * { + * if (parcObject_Lock(object)) { + * ... + * if (parcObject_Wait(object) { + * .... + * } + * ... + * parcObject_Unlock(object); + * } + * } + * @endcode + */ +void parcObject_Wait(const PARCObject *object); + +/** + * @def parcObject_ImplementWait + * + * parcObject_ImplementWait is a helper C-macro that defines a static, inline facade for the `parcObject_Wait` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type string (e.g. `PARCBuffer`) + * @see parcObject_Wait + */ +#define parcObject_ImplementWait(_namespace, _type) \ + static inline void _namespace ## _Wait(const _type * pObject) { \ + parcObject_Wait((const PARCObject *) pObject); \ + } typedef void parcCMacro_Cat (_type, _Wait_NOOP) + + +/** + * Causes the calling thread to wait until either another thread invokes the `parcObject_Notify()` + * function on the same object or the system time equals or exceeds the specified time. + * + * The calling thread must own the object's lock. + * The calling thread will release ownership of this lock and wait until another thread invokes + * `parcObject_Notify` or the computer's system time equals or exceeds that specified by @p time. + * 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] object A pointer to a valid PARCObject instance. + * + * @returns false if the alloted time was exceeded. + * @returns true if another thread invoked the `parcObject_Notify()` function + * + * Example: + * @code + * { + * struct timeval tv; + * gettimeofday(&tv, NULL); + * + * struct timespec absoluteTime; + * absoluteTime.tv_sec = tv.tv_sec + 0; + * absoluteTime.tv_nsec = 0; + * + * parcObject_WaitUntil(object, &absoluteTime); + * } + * @endcode + */ +bool parcObject_WaitUntil(const PARCObject *object, const struct timespec *time); + +/** + * @def parcObject_ImplementWaitUntil + * + * parcObject_ImplementWaitUntil is a helper C-macro that defines a static, inline facade for the + * `parcObject_WaitUntil` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type string (e.g. `PARCBuffer`) + * @see parcObject_WaitUntil + */ +#define parcObject_ImplementWaitUntil(_namespace, _type) \ + static inline bool _namespace ## _WaitUntil(const _type * pObject, const struct timespec *time) { \ + return parcObject_WaitUntil((const PARCObject *) pObject, time); \ + } typedef void parcCMacro_Cat (_type, _WaitUntil_NOOP) + +/** + * Causes the calling thread to wait until either another thread invokes the `parcObject_Notify()` + * function on the same object or the given number of nanoseconds elapses. + * + * The calling thread must own the object's lock. + * + * The calling thread will release ownership of its lock and wait until another thread invokes + * `parcObject_Notify` on the same object, + * or the computer's system time equals or exceeds the time specified by the + * time of invocation plus nanoSeconds. + * 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] object A pointer to a valid PARCObject instance. + * @param [in] nanoSeconds The number of nanoseconds to wait. + * + * @returns false if the allotted time was exceeded. + * @returns true if another thread invoked the `parcObject_Notify()` function + * + * Example: + * @code + * { + * parcObject_WaitFor(object, 1000000000UL); + * } + * @endcode + */ +bool parcObject_WaitFor(const PARCObject *object, const uint64_t nanoSeconds); + +/** + * @def parcObject_ImplementWaitUntil + * + * parcObject_ImplementWaitUntil is a helper C-macro that defines a static, inline facade for the + * `parcObject_WaitUntil` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type string (e.g. `PARCBuffer`) + * @see parcObject_WaitUntil + */ +#define parcObject_ImplementWaitFor(_namespace, _type) \ + static inline bool _namespace ## _WaitFor(const _type * pObject, const unsigned long nanoSeconds) { \ + return parcObject_WaitFor((const PARCObject *) pObject, nanoSeconds); \ + } typedef void parcCMacro_Cat (_type, _WaitFor_NOOP) + +/** + * 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] object A pointer to a valid `PARCObject` instance. + * + * Example: + * @code + * { + * if (parcObject_Lock(object)) { + * parcObject_Notify(object); + * parcObject_Unlock(object); + * } + * } + * @endcode + */ +void parcObject_Notify(const PARCObject *object); + +/** + * @def parcObject_ImplementNotify + * + * parcObject_ImplementNotify is a helper C-macro that defines a static, inline facade for the `parcObject_Notify` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type string (e.g. `PARCBuffer`) + */ +#define parcObject_ImplementNotify(_namespace, _type) \ + static inline void _namespace ## _Notify(const _type * pObject) { \ + parcObject_Notify((const PARCObject *) pObject); \ + } typedef void parcCMacro_Cat (_type, _Notify_NOOP) + + +/** + * Wakes up all threads that are waiting on the given object's lock. + * + * A thread waits on an object by calling one of the wait methods, `parcObject_Wait`, `parcObject_WaitFor`, `parcObject_WaitUntil`. + * The awakened threads will proceed after the current thread relinquishes the lock on the given object. + * The awakened threads will compete in the usual manner with any other threads that might be actively competing + * to synchronize on this object. + * Awakened threads have no priority between them in being the next thread to lock this object. + * + * This method can only be called by a thread that is the owner of this object's lock. + * + * @param [in] object A pointer to a valid `PARCObject` instance. + * + * Example: + * @code + * { + * if (parcObject_Lock(object)) { + * parcObject_NotifyAll(object); + * parcObject_Unlock(object); + * } + * } + * @endcode + */ +void parcObject_NotifyAll(const PARCObject *object); + +/** + * @def parcObject_ImplementNotifyAll + * + * parcObject_ImplementNotifyAll is a helper C-macro that defines a static, inline facade for the `parcObject_NotifyAll` function. + * + * @param [in] _namespace A subtype's namespace string (e.g. `parcBuffer`) + * @param [in] _type A subtype's type (e.g. `PARCBuffer`) + */ +#define parcObject_ImplementNotifyAll(_namespace, _type) \ + static inline void _namespace ## _NotifyAll(const _type * pObject) { \ + parcObject_NotifyAll((const PARCObject *) pObject); \ + } typedef void parcCMacro_Cat (_type, _NotifyAll_NOOP) + +/** + * @def parcObject_Mutex + * + * This macro uses the functions `parcObject_Lock` and `parcObject_Unlock` + * to provide a simple syntax for implementing a mutual exclusion region of code. + * + * @param [in] _object_ A pointer to a valid PARCObject that implements locking. + * + * Example: + * @code + * { + * parcObject_Mutex(object) { + * .... + * } + * } + * @endcode + * @see parcObject_Synchronize + */ +#define parcObject_Mutex(_object_) for (bool once = true; once && parcObject_Lock(_object_); parcObject_Unlock(_object_), once = false) + +/** + * Determine if a given `PARCObject` is and instance of the specified `PARCObjectDescriptor`. + * + * @param [in] object A pointer to a valid PARCObject instance. + * @param [in] descriptor A pointer to a valid PARCObjectDescriptor instance. + * + * @return true @p object is an instance of @p descriptor. + * @return false @p object is not an instance of @p descriptor. + */ +bool parcObject_IsInstanceOf(const PARCObject *object, const PARCObjectDescriptor *descriptor); + +/** + * Atomically set an object's barrier. + * + * If the barrier is not set, the barrier will be set and this function returns `true`. + * + * If the barrier is already set, any subsequent attempt to set the barrier will block until the barrier is unset + * (see `parcObject_BarrierUnset`). + * If there are multiple competitors to set the barrier, + * only one will (indiscriminately) succeed and return and the remaining will continue to attempt to set the barrier. + * + * Barriers can be used in both threaded and non-threaded applications, + * but are not a substitute for thread locking and do not interoperate the wait and notify operations. + * + * Barriers should be used in pairs within the same level of program abstraction to avoid confusion. + * It is possible to set a barrier without ever unsetting the same barrier, + * and as a consequence any other attempt to set the same barrier will hang the program. + * + * @param [in] object A pointer to a valid PARCObject + * + * @return true + * + * Example: + * @code + * { + * parcObject_BarrierSet(object); + * + * ... + * + * parcObject_BarrierUnset(object); + * } + * @endcode + * @see parcObject_BarrierUnset + * @see parcObject_Synchronize + */ +bool parcObject_BarrierSet(const PARCObject *object); + +/** + * Unset an objects' barrier. + * + * If a barrier is set (see `parcObject_BarrierSet`), the barrier is unset (see `parcObject_BarrierUnset`). + * + * If a barrier is not set, this function will block until the barrier is set, + * whereupon it will be immediately unset the barrier and return. + * + * If there are multiple competitors attempting to unset the barrier, + * only one will (indiscriminately) succeed and return and the remaining will continue to attempt to unset the barrier. + * + * Barriers are not a substitute for thread locking and do not interoperate the wait and notify operations. + * + * + * @param [in] object A pointer to a valid `PARCObject` + * + * @return false + * + * Example: + * @code + * { + * parcObject_BarrierSet(object); + * + * ... + * + * parcObject_BarrierUnset(object); + * } + * @endcode + */ +bool parcObject_BarrierUnset(const PARCObject *object); + +/** + * Synchronize on a `PARCObject` instance to provide a simple mutual exclusion region of code. + * + * This macro uses the functions `parcObject_BarrierSet` and `parcObject_BarrierUnset` + * to provide a simple syntax for implementing a mutual exclusion region of code. + * + * This defines and uses the local variable `_parcObjectSynchronize` which will always appear to be true to the calling function + * and must never be defined by the calling function, or any module. + * + * @param [in] object A pointer to a valid `PARCObject` + * + * Example: + * @code + * { + * parcObject_Synchronize(_object_) { + * // Only one thread executes this code at a single time. + * } + * } + * @endcode + * @see parcObject_Mutex + */ +#define parcObject_Synchronize(_object_) for (bool _parcObjectSynchronize = parcObject_BarrierSet(_object_); _parcObjectSynchronize; _parcObjectSynchronize = parcObject_BarrierUnset(_object_)) + +#endif // libparc_parc_Object_h |