mirror of https://github.com/yshui/picom.git
44 lines
1.6 KiB
C
44 lines
1.6 KiB
C
#pragma once
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#include <uthash.h>
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#include "utils.h"
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#define cache_entry(ptr, type, member) container_of(ptr, type, member)
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struct cache;
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struct cache_handle;
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/// User-provided function to fetch a value for the cache, when it's not present.
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/// Should return 0 if the value is fetched successfully, and a negative number if the
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/// value cannot be fetched. Getter doesn't need to initialize fields of `struct
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/// cache_handle`.
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typedef int (*cache_getter_t)(struct cache *, const char *key, size_t keylen,
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struct cache_handle **value, void *user_data);
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typedef void (*cache_free_t)(struct cache *, struct cache_handle *value);
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struct cache {
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struct cache_handle *entries;
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};
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static const struct cache CACHE_INIT = {NULL};
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struct cache_handle {
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char *key;
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UT_hash_handle hh;
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};
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/// Get a value from the cache. If the value doesn't present in the cache yet, the
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/// getter will be called, and the returned value will be stored into the cache.
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/// Returns 0 if the value is already present in the cache, 1 if the value is fetched
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/// successfully, and a negative number if the value cannot be fetched.
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int cache_get_or_fetch(struct cache *, const char *key, size_t keylen,
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struct cache_handle **value, void *user_data, cache_getter_t getter);
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/// Get a value from the cache. If the value doesn't present in the cache, NULL will be
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/// returned.
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struct cache_handle *cache_get(struct cache *, const char *key, size_t keylen);
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/// Invalidate all values in the cache. After this call, `struct cache` holds no allocated
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/// memory, and can be discarded.
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void cache_invalidate_all(struct cache *, cache_free_t free_fn);
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