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[libhybris] Add cache for socket based property lookups.
Android properties are looked up over socket connection by default, which incurs considerable overhead if property lookup is very frequent. This commit adds similar property cache to socket based lookups as is used for direct file lookups. The cache invalidates its contents with a user definable timeout, making sure property changes are eventually propagated to all processes. By default the cache is not enabled, but can be enabled with --enable-property-cache configure switch.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,180 @@ | ||
| /* | ||
| * Copyright (c) 2012 Carsten Munk <carsten.munk@gmail.com> | ||
| * Copyright (c) 2008 The Android Open Source Project | ||
| * Copyright (c) 2013 Simon Busch <morphis@gravedo.de> | ||
| * Copyright (c) 2013 Canonical Ltd | ||
| * Copyright (c) 2013 Jolla Ltd. <robin.burchell@jollamobile.com> | ||
| * Copyright (c) 2015 Jolla Ltd. <mikko.harju@jollamobile.com> | ||
| * | ||
| * 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. | ||
| * | ||
| */ | ||
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| #include <stdlib.h> | ||
| #include <assert.h> | ||
| #include <errno.h> | ||
| #include <string.h> | ||
| #include <time.h> | ||
| #include <pthread.h> | ||
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| #define HYBRIS_PROPERTY_CACHE_DEFAULT_TIMEOUT_SECS 10 | ||
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| /** Maximum allowed time to return stale data from the cache. Override | ||
| with HYBRIS_PROPERTY_CACHE_TIMEOUT_SECS environment variable. | ||
| */ | ||
| static time_t runtime_cache_timeout_secs = HYBRIS_PROPERTY_CACHE_DEFAULT_TIMEOUT_SECS; | ||
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| /** Key, value pair and the time of previous update (in seconds) */ | ||
| struct hybris_prop_value | ||
| { | ||
| char *key; | ||
| char *value; | ||
| time_t last_update; | ||
| }; | ||
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| static struct hybris_prop_value * prop_array = 0; | ||
| static int num_prop = 0; | ||
| static int num_alloc = 0; | ||
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| /** Protect access to statics */ | ||
| static pthread_mutex_t array_mutex = PTHREAD_MUTEX_INITIALIZER; | ||
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| /* private: | ||
| * compares two hybris_prop_value by key, so as to maintain a qsorted array of | ||
| * props, and search the array. | ||
| */ | ||
| static int prop_qcmp(const void *a, const void *b) | ||
| { | ||
| struct hybris_prop_value *aa = (struct hybris_prop_value *)a; | ||
| struct hybris_prop_value *bb = (struct hybris_prop_value *)b; | ||
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| return strcmp(aa->key, bb->key); | ||
| } | ||
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| static struct hybris_prop_value *cache_find_internal(const char *key) | ||
| { | ||
| struct hybris_prop_value prop_key; | ||
| prop_key.key = (char*)key; | ||
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| return bsearch(&prop_key, prop_array, num_prop, sizeof(struct hybris_prop_value), prop_qcmp); | ||
| } | ||
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| static void runtime_cache_init() | ||
| { | ||
| num_alloc = 8; | ||
| prop_array = malloc(num_alloc * sizeof(struct hybris_prop_value)); | ||
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| const char *timeout_str = getenv("HYBRIS_PROPERTY_CACHE_TIMEOUT_SECS"); | ||
| if (timeout_str) { | ||
| runtime_cache_timeout_secs = atoi(timeout_str); | ||
| } | ||
| } | ||
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| static void runtime_cache_ensure_initialized() | ||
| { | ||
| if (!prop_array) { | ||
| runtime_cache_init(); | ||
| } | ||
| } | ||
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| /** Invalidate an entry in the cache | ||
| * | ||
| * Cache will never shrink. Instead, assume that the same key | ||
| * will be queried soon after invalidation and reuse the entry. | ||
| */ | ||
| static void runtime_cache_invalidate_entry(struct hybris_prop_value *entry) | ||
| { | ||
| free(entry->value); | ||
| entry->value = NULL; | ||
| } | ||
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| static int runtime_cache_get_impl(const char *key, char *value) | ||
| { | ||
| int ret = -ENOENT; | ||
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| struct hybris_prop_value *entry = cache_find_internal(key); | ||
| if (entry != NULL && entry->value != NULL) { | ||
| struct timespec now; | ||
| clock_gettime(CLOCK_MONOTONIC_COARSE, &now); | ||
| time_t delta_secs = now.tv_sec - entry->last_update; | ||
| if (delta_secs > runtime_cache_timeout_secs) { | ||
| // assume the data in cache is stale, and force refresh | ||
| runtime_cache_invalidate_entry(entry); | ||
| } else { | ||
| // success, return value from cache | ||
| strcpy(value, entry->value); | ||
| ret = 0; | ||
| } | ||
| } | ||
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| return ret; | ||
| } | ||
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| static void runtime_cache_insert_impl(const char *key, char *value) | ||
| { | ||
| struct timespec now; | ||
| clock_gettime(CLOCK_MONOTONIC_COARSE, &now); | ||
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| struct hybris_prop_value *entry = cache_find_internal(key); | ||
| if (entry) { | ||
| assert(entry->value == NULL); | ||
| // key,value pair was invalidated earlier, | ||
| // reuse entry in the property array | ||
| entry->value = strdup(value); | ||
| entry->last_update = now.tv_sec; | ||
| } else { | ||
| if (num_alloc == num_prop) { | ||
| num_alloc = 3 * num_alloc / 2; | ||
| prop_array = realloc(prop_array, num_alloc * sizeof(struct hybris_prop_value)); | ||
| } | ||
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| struct hybris_prop_value new_entry = { strdup(key), strdup(value), now.tv_sec }; | ||
| prop_array[num_prop++] = new_entry; | ||
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| qsort(prop_array, num_prop, sizeof(struct hybris_prop_value), prop_qcmp); | ||
| } | ||
| } | ||
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| void runtime_cache_lock() | ||
| { | ||
| pthread_mutex_lock(&array_mutex); | ||
| } | ||
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| void runtime_cache_unlock() | ||
| { | ||
| pthread_mutex_unlock(&array_mutex); | ||
| } | ||
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| void runtime_cache_remove(const char *key) | ||
| { | ||
| runtime_cache_ensure_initialized(); | ||
| struct hybris_prop_value *entry = cache_find_internal(key); | ||
| if (entry) { | ||
| runtime_cache_invalidate_entry(entry); | ||
| } | ||
| } | ||
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| int runtime_cache_get(const char *key, char *value) | ||
| { | ||
| runtime_cache_ensure_initialized(); | ||
| return runtime_cache_get_impl(key, value); | ||
| } | ||
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| void runtime_cache_insert(const char *key, char *value) | ||
| { | ||
| runtime_cache_ensure_initialized(); | ||
| runtime_cache_insert_impl(key, value); | ||
| } |