Connection manager (#50)

* connection manager implementation and tests

include/aws/http/connection_manager.h

@@ -0,0 +1,113 @@
+#ifndef AWS_HTTP_CONNECTION_MANAGER_H
+#define AWS_HTTP_CONNECTION_MANAGER_H
+
+/*
+ * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file 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.
+ */
+
+#include <aws/http/http.h>
+
+#include <aws/common/byte_buf.h>
+
+struct aws_client_bootstrap;
+struct aws_http_connection;
+struct aws_http_connection_manager;
+struct aws_http_connection_manager_mocks;
+struct aws_socket_options;
+struct aws_tls_connection_options;
+
+typedef void(aws_http_connection_manager_on_connection_setup_fn)(
+    struct aws_http_connection *connection,
+    int error_code,
+    void *user_data);
+
+/*
+ * Connection manager configuration struct.
+ *
+ * Contains all of the configuration needed to create an http connection as well as
+ * the maximum number of connections to ever have in existence.
+ */
+struct aws_http_connection_manager_options {
+    /*
+     * http connection configuration
+     */
+    struct aws_client_bootstrap *bootstrap;
+    size_t initial_window_size;
+    struct aws_socket_options *socket_options;
+    struct aws_tls_connection_options *tls_connection_options;
+    struct aws_byte_cursor host;
+    uint16_t port;
+
+    /*
+     * Maximum number of connections this manager is allowed to contain
+     */
+    size_t max_connections;
+};
+
+AWS_EXTERN_C_BEGIN
+
+/*
+ * Connection managers are ref counted.  Adds one external ref to the manager.
+ */
+AWS_HTTP_API
+void aws_http_connection_manager_acquire(struct aws_http_connection_manager *manager);
+
+/*
+ * Connection managers are ref counted.  Removes one external ref from the manager.
+ *
+ * When the ref count goes to zero, the connection manager begins its shut down
+ * process.  All pending connection acquisitions are failed (with callbacks
+ * invoked) and any (erroneous) subsequent attempts to acquire a connection
+ * fail immediately.  The connection manager destroys itself once all pending
+ * asynchronous activities have resolved.
+ */
+AWS_HTTP_API
+void aws_http_connection_manager_release(struct aws_http_connection_manager *manager);
+
+/*
+ * Creates a new connection manager with the supplied configuration options.
+ *
+ * The returned connection manager begins with a ref count of 1.
+ */
+AWS_HTTP_API
+struct aws_http_connection_manager *aws_http_connection_manager_new(
+    struct aws_allocator *allocator,
+    struct aws_http_connection_manager_options *options);
+
+/*
+ * Requests a connection from the manager.  The requester is notified of
+ * an acquired connection (or failure to acquire) via the supplied callback.
+ *
+ * Once a connection has been successfully acquired from the manager it
+ * must be released back (via aws_http_connection_manager_release_connection)
+ * at some point.  Failure to do so will cause a resource leak.
+ */
+AWS_HTTP_API
+void aws_http_connection_manager_acquire_connection(
+    struct aws_http_connection_manager *manager,
+    aws_http_connection_manager_on_connection_setup_fn *callback,
+    void *user_data);
+
+/*
+ * Returns a connection back to the manager.  All acquired connections must
+ * eventually be released back to the manager in order to avoid a resource leak.
+ */
+AWS_HTTP_API
+int aws_http_connection_manager_release_connection(
+    struct aws_http_connection_manager *manager,
+    struct aws_http_connection *connection);
+
+AWS_EXTERN_C_END
+
+#endif /* AWS_HTTP_CONNECTION_MANAGER_H */

include/aws/http/http.h

@@ -31,6 +31,9 @@ enum aws_http_errors {
     AWS_ERROR_HTTP_CALLBACK_FAILURE,
     AWS_ERROR_HTTP_WEBSOCKET_CLOSE_FRAME_SENT,
     AWS_ERROR_HTTP_WEBSOCKET_IS_MIDCHANNEL_HANDLER,
+    AWS_ERROR_HTTP_CONNECTION_MANAGER_INVALID_STATE_FOR_ACQUIRE,
+    AWS_ERROR_HTTP_CONNECTION_MANAGER_VENDED_CONNECTION_UNDERFLOW,
+
     AWS_ERROR_HTTP_END_RANGE = 0x0C00,
 };
 
@@ -39,6 +42,7 @@ enum aws_http_log_subject {
     AWS_LS_HTTP_CONNECTION,
     AWS_LS_HTTP_SERVER,
     AWS_LS_HTTP_STREAM,
+    AWS_LS_HTTP_CONNECTION_MANAGER,
     AWS_LS_HTTP_WEBSOCKET,
 };
 

include/aws/http/private/connection_manager_function_table.h

@@ -0,0 +1,51 @@
+#ifndef AWS_HTTP_CONNECTION_MANAGER_FUNCTION_TABLE_H
+#define AWS_HTTP_CONNECTION_MANAGER_FUNCTION_TABLE_H
+
+/*
+ * Copyright 2010-2019 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License").
+ * You may not use this file except in compliance with the License.
+ * A copy of the License is located at
+ *
+ *  http://aws.amazon.com/apache2.0
+ *
+ * or in the "license" file accompanying this file. This file 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.
+ */
+
+#include <aws/http/http.h>
+
+#include <aws/http/connection.h>
+
+typedef int(aws_http_connection_manager_create_connection_fn)(const struct aws_http_client_connection_options *options);
+typedef void(aws_http_connection_manager_close_connection_fn)(struct aws_http_connection *connection);
+typedef void(aws_http_connection_manager_release_connection_fn)(struct aws_http_connection *connection);
+typedef bool(aws_http_connection_manager_is_connection_open_fn)(const struct aws_http_connection *connection);
+
+struct aws_http_connection_manager_function_table {
+    /*
+     * Downstream http functions
+     */
+    aws_http_connection_manager_create_connection_fn *create_connection;
+    aws_http_connection_manager_close_connection_fn *close_connection;
+    aws_http_connection_manager_release_connection_fn *release_connection;
+    aws_http_connection_manager_is_connection_open_fn *is_connection_open;
+};
+
+AWS_HTTP_API
+bool aws_http_connection_manager_function_table_is_valid(
+    const struct aws_http_connection_manager_function_table *table);
+
+AWS_HTTP_API
+void aws_http_connection_manager_set_function_table(
+    struct aws_http_connection_manager *manager,
+    const struct aws_http_connection_manager_function_table *function_table);
+
+AWS_HTTP_API
+extern const struct aws_http_connection_manager_function_table
+    *g_aws_http_connection_manager_default_function_table_ptr;
+
+#endif /* AWS_HTTP_CONNECTION_MANAGER_FUNCTION_TABLE_H */