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/** @copyright
* Copyright (c) 2015, Intel Corporation
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation and/or
* other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its contributors
* may be used to endorse or promote products derived from this software without
* specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/** @file
*
* Simplified parameter framework C API. This API does not target a perfect
* one/one mapping with the c++ one, but rather aim ease of use and type safety
* (as far as possible in c). All function are reentrant and function call on
* a pfw (PfwHandle) does not impact any other pfw. Ie. There is no shared
* resources between pfw instances.
*/
#pragma once
#ifdef __cplusplus
extern "C" {
#endif
#include "cparameter_export.h"
#include <stdbool.h>
#include <stdint.h>
#include <stddef.h>
/** Lots of function in this API require non null pointer parameter.
* Such arguments are marked NONNULL.
*/
#if defined(__clang__) || defined(__GNUC__)
#define NONNULL __attribute__((nonnull))
#define NONNULL_(...) __attribute__((nonnull(__VA_ARGS__)))
#define USERESULT __attribute__((warn_unused_result))
#elif defined(_MSC_VER)
// In visual studio's cl there is no
// equivalent of nonnull
#define NONNULL
#define NONNULL_(...)
#define USERESULT _Check_return_
#else
#error "Unknown compilator"
#endif
/** Private handle to a parameter framework.
* A PfwHandler* is valid if:
* - it was created by pfwCreate
* - it has not been destroyed by pfwDestroyParameter
* - is not NULL
* A valid handle MUST be provided to all pfw related method.
* A valid handler MUST be destroyed with pfwDestroy before programme
* termination.
* @note Forward declaration to break header dependency.
*/
struct PfwHandler_;
/** Typedef for use ease. @see PfwHandler_. */
typedef struct PfwHandler_ PfwHandler;
///////////////////////////////
///////////// Log /////////////
///////////////////////////////
/** Pfw log level for the callback. */
typedef enum {
pfwLogInfo = 55, //< Random value to avoid unfortunate mismatch.
pfwLogWarning
} PfwLogLevel;
/** Type of the parameter framework log callback.
* @param[in] userCtx Arbitrary context provided during callback registration.
* @param[in] level Log level of the log line.
* @param[in] logLine Log line (without end line control character like '\n')
* to be logged. The pointer is invalidate after function
* return or if any pfw function is called.
*/
typedef void PfwLogCb(void *userCtx, PfwLogLevel level, const char *logLine);
/** Logger containing a callback method and its context. */
typedef struct
{
/** User defined arbitrary value that will be provided to all logCb call. */
void *userCtx;
/** Callback that will be called.
* If NULL nothing will be logged.
*/
PfwLogCb *logCb;
} PfwLogger;
///////////////////////////////
///////////// Core ////////////
///////////////////////////////
/** Structure of a parameter framework criterion. */
typedef struct
{
/** Name of the criterion in the pfw configuration rules. */
const char *name; //< Must not be null.
bool inclusive; //< True if the criterion is inclusive, false if exclusive.
/** Null terminated list of criterion value names.
*
* Example:
* @verbatim
* { "Red", "Green", "Blue", NULL }
* @endverbatim
*
* For an exclusive criterion, the list must not contain more elements then
* INT_MAX.
* For an inclusive criterion, the list must not contain more elements then
* sizeof(int) * BIT_CHAR - 1.
* Ie: (int)1 << n must *not* overflow (UB),
* were n is the number of element in the
* list. @see pfwSetCriterion
*/
const char **values; //< Must not be null.
} PfwCriterion;
/** Create a parameter framework instance.
* Can not fail except for memory allocation.
*/
CPARAMETER_EXPORT
PfwHandler *pfwCreate() USERESULT;
/** Destroy a parameter framework. Can not fail. */
CPARAMETER_EXPORT
void pfwDestroy(PfwHandler *handle) NONNULL;
/** Start a parameter framework.
* @param[in] handle @see PfwHandler
* @param[in] configPath Path to the file containing the pfw configuration.
* @param[in] criteria An array of PfwCriterion.
* @param[in] criterionNb The number of PfwCriterion in criteria.
* @param[in] logger the logger to use for all operation.
* If NULL, log infos to standard output and
* errors to standard error.
* @return true on success, false on failure.
*/
CPARAMETER_EXPORT
bool pfwStart(PfwHandler *handle, const char *configPath, const PfwCriterion criteria[],
size_t criterionNb, const PfwLogger *logger) NONNULL_(1, 2, 3) USERESULT;
/** @return a string describing the last call result.
* If the last pfw function call succeeded, return an empty string.
* If the last pfw function call failed, return a message explaining the error cause.
* The return pointer is invalidated if any pfw method is called on the SAME
* PfwHandle.
*
* Each PfwHandle own it's last error message. It is not static nor TLS.
* As a result, calling a pfw function with a NULL PfwHandler will result in a
* failure WITHOUT updating the last error.
*/
CPARAMETER_EXPORT
const char *pfwGetLastError(const PfwHandler *handle) NONNULL;
/** Set a criterion value given its name and value.
* @param[in] handle @see PfwHandler
* @param[in] name The name of the criterion that need to be changed.
* @param[in] value If the criterion is exclusive, the index of the new value.
* If the criterion is inclusive, a bit field where each bit
* correspond to the value index.
* For an inclusive criterion defined as such: { "Red", "Green", "Blue", NULL }
* to set the value Green and Blue, value has to be 1<<1 | 1<<2 = 0b110 = 6.
* For an exclusive criterion defined as such: { "Car", "Boat", "Plane", NULL }
* to set the value Plane, value has to be 2.
*
* Criterion change do not have impact on the parameters value
* (no configuration applied) until the changes are committed using pfwApplyConfigurations.
*
* @return true on success and false on failure.
*/
CPARAMETER_EXPORT
bool pfwSetCriterion(PfwHandler *handle, const char name[], int value) NONNULL USERESULT;
/** Get a criterion value given its name.
* Same usage as pfwSetCriterion except that value is an out param.
* Get criterion will return the last value setted with pfwSetCriterion independantly of
* pfwCommitCritenio.
*/
CPARAMETER_EXPORT
bool pfwGetCriterion(const PfwHandler *handle, const char name[], int *value) NONNULL USERESULT;
/** Commit criteria change and change parameters according to the configurations.
* Criterion do not have impact on the parameters value when changed,
* instead they are staged and only feed to the rule engine
* (who then impact parameter values according to the configuration) when
* committed with this function.
*
* @param[in] handle @see PfwHandler
* @return true on success and false on failure.
*/
CPARAMETER_EXPORT
bool pfwApplyConfigurations(const PfwHandler *handle) NONNULL USERESULT;
///////////////////////////////
/////// Parameter access //////
///////////////////////////////
/** Handler to a pfw parameter.
* A PfwParameterHandler* is valid if:
* - it was created by pfwBindParameter
* - it has not been destroyed by pfwDestroyParameter
* - is not NULL
* - the pfwHandle used to created is still valid (ie. it must not outlive
* its parent pfw)
* A valid handle MUST be provided to all pfw parameter related method.
* Any created handle MUST be destroyed (with pfwDestroyParameter) before
* the PfwHandler that was used for its creation.
* @note Forward declaration to break header dependency.
*/
struct PfwParameterHandler_;
typedef struct PfwParameterHandler_ PfwParameterHandler;
/** Construct the handle to a parameter given its path.
* The PfwHandle MUST stay valid until PfwParameterHandler destruction.
* @return a PfwParameterHandler on success, NULL on error.
* @see pfwGetLastError for error detail.
*/
CPARAMETER_EXPORT
PfwParameterHandler *pfwBindParameter(PfwHandler *handle, const char path[]) NONNULL;
/** Destroy a parameter handle. Can not fail. */
CPARAMETER_EXPORT
void pfwUnbindParameter(PfwParameterHandler *handle) NONNULL;
/** Access the value of a previously bind int parameter.
* @param[in] handle Handler to a valid parameter.
* @param[in] value Non null pointer to an integer that will
* hold the parameter value on success, undefined otherwise.
* return true of success, false on failure.
*/
CPARAMETER_EXPORT
bool pfwGetIntParameter(const PfwParameterHandler *handle, int32_t *value) NONNULL USERESULT;
/** Set the value of a previously bind int parameter.
* @param[in] handle Handler to a valid parameter.
* @param[in] value The parameter value to set.
* return true of success, false on failure.
*/
CPARAMETER_EXPORT
bool pfwSetIntParameter(PfwParameterHandler *handle, int32_t value) NONNULL USERESULT;
/** Access the value of a previously bind string parameter.
* @param[in] handle Handler to a valid parameter.
* @param[out] value Non null pointer on a string.
* Will point on the parameter value string on success,
* NULL on failure.
* The callee MUST free the returned string using pfwFree after use.
* @return true on success, false on failure.
*/
CPARAMETER_EXPORT
bool pfwGetStringParameter(const PfwParameterHandler *handle, char *value[]) NONNULL;
/** Set the value of a previously bind string parameter.
* @param[in] handle Handler to a valid parameter
* @param[in] value Non null pointer to a null terminated string to set.
*/
CPARAMETER_EXPORT
bool pfwSetStringParameter(PfwParameterHandler *handle, const char value[]) NONNULL USERESULT;
/** Frees the memory space pointed to by ptr,
* which must have been returned by a previous call to the pfw.
*
* @param[in] ptr pointer to the memory to free.
* @see man 3 free for usage.
* @note Wrapper around the standard free to avoid problems
* in case of a different pfw and client allocator.
*/
CPARAMETER_EXPORT
void pfwFree(void *ptr);
#undef NONNULL
#undef NONNULL_
#undef USERESULT
#ifdef __cplusplus
}
#endif