intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 59 insertions, 0 deletions

diff --git a/contrib/restricted/aws/aws-c-common/source/fifo_cache.c b/contrib/restricted/aws/aws-c-common/source/fifo_cache.c
new file mode 100644
index 00000000000..9627c5ad63a
--- /dev/null
+++ b/contrib/restricted/aws/aws-c-common/source/fifo_cache.c
@@ -0,0 +1,59 @@
+/**
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0.
+ */
+#include <aws/common/fifo_cache.h>
+
+static int s_fifo_cache_put(struct aws_cache *cache, const void *key, void *p_value);
+
+static struct aws_cache_vtable s_fifo_cache_vtable = {
+    .destroy = aws_cache_base_default_destroy,
+    .find = aws_cache_base_default_find,
+    .put = s_fifo_cache_put,
+    .remove = aws_cache_base_default_remove,
+    .clear = aws_cache_base_default_clear,
+    .get_element_count = aws_cache_base_default_get_element_count,
+};
+
+struct aws_cache *aws_cache_new_fifo(
+    struct aws_allocator *allocator,
+    aws_hash_fn *hash_fn,
+    aws_hash_callback_eq_fn *equals_fn,
+    aws_hash_callback_destroy_fn *destroy_key_fn,
+    aws_hash_callback_destroy_fn *destroy_value_fn,
+    size_t max_items) {
+    AWS_ASSERT(allocator);
+    AWS_ASSERT(max_items);
+
+    struct aws_cache *fifo_cache = aws_mem_calloc(allocator, 1, sizeof(struct aws_cache));
+    if (!fifo_cache) {
+        return NULL;
+    }
+    fifo_cache->allocator = allocator;
+    fifo_cache->max_items = max_items;
+    fifo_cache->vtable = &s_fifo_cache_vtable;
+    if (aws_linked_hash_table_init(
+            &fifo_cache->table, allocator, hash_fn, equals_fn, destroy_key_fn, destroy_value_fn, max_items)) {
+        return NULL;
+    }
+    return fifo_cache;
+}
+
+/* fifo cache put implementation */
+static int s_fifo_cache_put(struct aws_cache *cache, const void *key, void *p_value) {
+    if (aws_linked_hash_table_put(&cache->table, key, p_value)) {
+        return AWS_OP_ERR;
+    }
+
+    /* Manage the space if we actually added a new element and the cache is full. */
+    if (aws_linked_hash_table_get_element_count(&cache->table) > cache->max_items) {
+        /* we're over the cache size limit. Remove whatever is in the front of
+         * the linked_hash_table, which is the oldest element */
+        const struct aws_linked_list *list = aws_linked_hash_table_get_iteration_list(&cache->table);
+        struct aws_linked_list_node *node = aws_linked_list_front(list);
+        struct aws_linked_hash_table_node *table_node = AWS_CONTAINER_OF(node, struct aws_linked_hash_table_node, node);
+        return aws_linked_hash_table_remove(&cache->table, table_node->key);
+    }
+
+    return AWS_OP_SUCCESS;
+}