Add service locator component
Change-Id: I58ad588deff3c0904b3ba8b9162b20440e9ff7d3
Signed-off-by: Julian Hall <julian.hall@arm.com>
diff --git a/components/service/locator/interface/component.cmake b/components/service/locator/interface/component.cmake
new file mode 100644
index 0000000..b5aefa3
--- /dev/null
+++ b/components/service/locator/interface/component.cmake
@@ -0,0 +1,17 @@
+#-------------------------------------------------------------------------------
+# Copyright (c) 2020, Arm Limited and Contributors. All rights reserved.
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#
+#-------------------------------------------------------------------------------
+if (NOT DEFINED TGT)
+ message(FATAL_ERROR "mandatory parameter TGT is not defined.")
+endif()
+
+set_property(TARGET ${TGT} PROPERTY SERVICE_LOCATOR_PUBLIC_HEADER_FILES
+ "${CMAKE_CURRENT_LIST_DIR}/service_locator.h"
+ )
+
+target_include_directories(${TGT} PUBLIC
+ "${CMAKE_CURRENT_LIST_DIR}"
+ )
diff --git a/components/service/locator/interface/service_locator.h b/components/service/locator/interface/service_locator.h
new file mode 100644
index 0000000..3e1404b
--- /dev/null
+++ b/components/service/locator/interface/service_locator.h
@@ -0,0 +1,115 @@
+/*
+ * Copyright (c) 2020, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef SERVICE_LOCATOR_H
+#define SERVICE_LOCATOR_H
+
+#include <rpc_caller.h>
+
+/*
+ * The service_locator puplic interface may be exported as a public interface to
+ * a shared library.
+ */
+#ifdef EXPORT_PUBLIC_INTERFACE_SERVICE_LOCATOR
+#define SERVICE_LOCATOR_EXPORTED __attribute__((__visibility__("default")))
+#else
+#define SERVICE_LOCATOR_EXPORTED
+#endif
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * The service_locator provides an interface for locating trusted service
+ * provider instances and establishing RPC sessions for using the service.
+ * The service_locator decouples clients from the details of any particular
+ * service deployment. By accessing trusted services using the service_locator,
+ * client code may be reused accross different service deployment scenarios.
+ */
+struct service_location_strategy;
+typedef void* rpc_session_handle;
+
+/*
+ * Initialises the singleton service locator. Must be called once
+ * but may be called more than once.
+ */
+SERVICE_LOCATOR_EXPORTED void service_locator_init(void);
+
+/*
+ * An environment specific implementation of this function is
+ * needed in order to initialise and register the set of
+ * concrete service_location_strategy objects to use when
+ * building a deployment for a particular environment.
+ */
+void service_locator_envinit(void);
+
+/*
+ * Register a service_location_strategy for locating service
+ * instances. When attempting to locate a service, the set
+ * of registered service_location_strategy objects will be tried
+ * in the order of registration.
+ */
+void service_locator_register_strategy(const struct service_location_strategy *strategy);
+
+/*
+ * Query to locate a service instance. If the given service name
+ * corresponds to an available service instance, a service_context
+ * is returned. The client should hang onto this until it has
+ * finished using the service. When the service is no longer needed,
+ * the client should call the relinquish method. Returns NULL
+ * if no service is located that corresponds to the service name.
+ */
+SERVICE_LOCATOR_EXPORTED struct service_context *service_locator_query(const char *sn, int *status);
+
+/*
+ * The service_context struct represents a service instance to a client
+ * after having located the service instance using the service locator. A
+ * service_context object allows a client to open and close RPC sessions
+ * associated with the service instance, wherever it happens to be deployed.
+ */
+struct service_context
+{
+ void *context;
+
+ rpc_session_handle (*open)(void *context, struct rpc_caller **caller);
+ void (*close)(void *context, rpc_session_handle session_handle);
+ void (*relinquish)(void *context);
+};
+
+/*
+ * Provides an abstract interface for a strategy that locates services
+ * in a particular way. The set of registered strategies forms a
+ * chain of responsibility for resolving a query made by a clisnt.
+ */
+struct service_location_strategy
+{
+ struct service_context *(*query)(const char *sn, int *status);
+};
+
+/*
+ * Open an RPC session in order to use the service associated with this
+ * service_context.
+ */
+SERVICE_LOCATOR_EXPORTED rpc_session_handle service_context_open(struct service_context *s, struct rpc_caller **caller);
+
+/*
+ * Close an RPC session.
+ */
+SERVICE_LOCATOR_EXPORTED void service_context_close(struct service_context *s, rpc_session_handle session_handle);
+
+/*
+ * Called by a client when it has finished using a service context.
+ */
+SERVICE_LOCATOR_EXPORTED void service_context_relinquish(struct service_context *context);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SERVICE_LOCATOR_H */