store.h

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#pragma once
 
#include <stddef.h>
 
#include <launchdarkly/boolean.h>
 
/*******************************************************************************
 * @name Store collections and individual items.
 * Used to provide an opaque interface for interacting with feature values.
 * @{
 ******************************************************************************/
 
struct LDStoreCollectionItem
{
    void *       buffer;
    size_t       bufferSize;
    unsigned int version;
};
 
struct LDStoreCollectionStateItem
{
    const char *                 key;
    struct LDStoreCollectionItem item;
};
 
struct LDStoreCollectionState
{
    const char *                       kind;
    struct LDStoreCollectionStateItem *items;
    unsigned int                       itemCount;
};
 
/*******************************************************************************
 * @name Generic Store Interface
 * Used to provide all interaction with a feature store. Redis, Consul, Dynamo.
 *
 * The associated functions use a boolean result to indicate success, or error
 * outside of expected functionality. For example a memory allocation error
 * would return false, but `get` on a non existent item would return true.
 * @{
 ******************************************************************************/
 
struct LDStoreInterface
{
    void *context;
    LDBoolean (*init)(
        void *const                          context,
        const struct LDStoreCollectionState *collections,
        const unsigned int                   collectionCount);
    LDBoolean (*get)(
        void *const                         context,
        const char *const                   kind,
        const char *const                   featureKey,
        struct LDStoreCollectionItem *const result);
    LDBoolean (*all)(
        void *const                          context,
        const char *const                    kind,
        struct LDStoreCollectionItem **const result,
        unsigned int *const                  resultCount);
    LDBoolean (*upsert)(
        void *const                               context,
        const char *const                         kind,
        const struct LDStoreCollectionItem *const feature,
        const char *const                         featureKey);
    LDBoolean (*initialized)(void *const context);
    void (*destructor)(void *const context);
};