Merge the sorcery data access layer API.

Sorcery is a unifying data access layer which provides a pluggable mechanism to allow
object creation, retrieval, updating, and deletion using different backends (or wizards).

This is a fancy way of saying "one interface to rule them all" where them is configuration,
realtime, and anything else that comes along.

Review: https://reviewboard.asterisk.org/r/2259/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@380069 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 537 insertions, 0 deletions

diff --git a/include/asterisk/sorcery.h b/include/asterisk/sorcery.h
new file mode 100644
index 000000000..1a1042fbd
--- /dev/null
+++ b/include/asterisk/sorcery.h
@@ -0,0 +1,537 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2012 - 2013, Digium, Inc.
+ *
+ * Joshua Colp <jcolp@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*! \file
+ * \brief Sorcery Data Access Layer API
+ * \author Joshua Colp <jcolp@digium.com>
+ * \ref AstSorcery
+ */
+
+/*!
+ * \page AstSorcery Data Access Layer API
+ *
+ * Sorcery is a unifying data access layer which utilizes the configuration framework,
+ * realtime, and astdb to allow object creation, retrieval, updating, and deletion.
+ *
+ * \par Initialization
+ *
+ * Usage of sorcery is accomplished by first opening a sorcery structure. This structure holds
+ * all information about the object types, object fields, and object mappings. All API functions
+ * require the sorcery structure to operate. When sorcery is no longer needed the structure can
+ * be unreferenced using \ref ast_sorcery_unref
+ *
+ * Once opened the sorcery structure must have object mappings applied to it. This maps the
+ * object types to their respective wizards (object storage modules). If the developer would like
+ * to allow the user to configure this using the sorcery.conf configuration file the
+ * \ref ast_sorcery_apply_config API call can be used to read in the configuration file and apply the
+ * mappings. If the storage of the object types are such that a default wizard can be used this can
+ * be applied using the \ref ast_sorcery_apply_default API call. Note that the default mappings will not
+ * override configured mappings. They are only used in the case where no configured mapping exists.
+ *
+ * Configuring object mappings implicitly creates a basic version of an object type. The object type
+ * must be fully registered, however, using the \ref ast_sorcery_object_type_register API call before any
+ * objects of the type can be allocated, created, or retrieved.
+ *
+ * Once the object type itself has been fully registered the individual fields within the object must
+ * be registered using the \ref ast_sorcery_object_field_register API call. Note that not all fields *need*
+ * be registered. Only fields that should be accessible using the sorcery API have to be registered.
+ *
+ * \par Creating Objects
+ *
+ * Before an object can be created within the sorcery API it must first be allocated using the
+ * \ref ast_sorcery_alloc API call. This allocates a new instance of the object, sets sorcery specific
+ * details, and applies default values to the object. A unique identifier can optionally be specified
+ * when allocating an object. If it is not provided one will be automatically generated. Allocating
+ * an object does not create it within any object storage mechanisms that are configured for the
+ * object type. Creation must explicitly be done using the \ref ast_sorcery_create API call. This API call
+ * passes the object to each configured object storage mechanism for the object type until one
+ * successfully persists the object.
+ *
+ * \par Retrieving Objects
+ *
+ * To retrieve a single object using its unique identifier the \ref ast_sorcery_retrieve_by_id API call
+ * can be used.
+ *
+ * To retrieve potentially multiple objects using specific fields the \ref ast_sorcery_retrieve_by_fields
+ * API call can be used. The behavior of this API call is controlled using different flags. If the
+ * AST_RETRIEVE_FLAG_MULTIPLE flag is used a container will be returned which contains all matching objects.
+ * To retrieve all objects the AST_RETRIEVE_FLAG_ALL flag can be specified. Note that when specifying this flag
+ * you do not need to pass any fields.
+ *
+ * Both API calls return shared objects. Modification of the object can not occur until it has been copied.
+ *
+ * \par Updating Objects
+ *
+ * As retrieved objects may be shared the first step to updating the object with new details is creating a
+ * copy using the \ref ast_sorcery_copy API call. This will return a new object which is specific to the caller.
+ * Any field within the object may be modified as needed. Once changes are done the changes can be committed
+ * using the \ref ast_sorcery_update API call. Note that as the copied object is specific to the caller it must
+ * be unreferenced after use.
+ *
+ * \par Deleting Objects
+ *
+ * To delete an object simply call the \ref ast_sorcery_delete API call with an object retrieved using the
+ * ast_sorcery_retrieve_by_* API calls or a copy returned from \ref ast_sorcery_copy.
+ */
+
+#ifndef _ASTERISK_SORCERY_H
+#define _ASTERISK_SORCERY_H
+
+#if defined(__cplusplus) || defined(c_plusplus)
+extern "C" {
+#endif
+
+#include "asterisk/config_options.h"
+#include "asterisk/uuid.h"
+
+/*! \brief Maximum size of an object type */
+#define MAX_OBJECT_TYPE 64
+
+/*!
+ * \brief Retrieval flags
+ */
+enum ast_sorcery_retrieve_flags {
+	/*! \brief Default retrieval flags */
+	AST_RETRIEVE_FLAG_DEFAULT = 0,
+
+	/*! \brief Return all matching objects */
+	AST_RETRIEVE_FLAG_MULTIPLE = (1 << 0),
+
+        /*! \brief Perform no matching, return all objects */
+        AST_RETRIEVE_FLAG_ALL = (1 << 1),
+};
+
+/*! \brief Forward declaration for the sorcery main structure */
+struct ast_sorcery;
+
+/*!
+ * \brief A callback function for translating a value into a string
+ *
+ * \param obj Object to get value from
+ * \param args Where the field is
+ * \param buf Pointer to the buffer that the handler has created which contains the field value
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+typedef int (*sorcery_field_handler)(const void *obj, const intptr_t *args, char **buf);
+
+/*!
+ * \brief A callback function for performing a transformation on an object set
+ *
+ * \param set The existing object set
+ *
+ * \retval non-NULL new object set if changed
+ * \retval NULL if no changes present
+ *
+ * \note The returned ast_variable list must be *new*. You can not return the input set.
+ */
+typedef struct ast_variable *(*sorcery_transform_handler)(struct ast_variable *set);
+
+/*!
+ * \brief A callback function for when an object set is successfully applied to an object
+ *
+ * \param sorcery Sorcery structure in use
+ * \param obj The object itself
+ */
+typedef void (*sorcery_apply_handler)(const struct ast_sorcery *sorcery, void *obj);
+
+/*! \brief Interface for a sorcery wizard */
+struct ast_sorcery_wizard {
+	/*! \brief Name of the wizard */
+	const char *name;
+
+	/*! \brief Pointer to the Asterisk module this wizard is implemented by */
+	struct ast_module *module;
+
+	/*! \brief Callback for opening a wizard */
+	void *(*open)(const char *data);
+
+	/*! \brief Optional callback for loading persistent objects */
+	void (*load)(void *data, const struct ast_sorcery *sorcery, const char *type);
+
+	/*! \brief Optional callback for reloading persistent objects */
+	void (*reload)(void *data, const struct ast_sorcery *sorcery, const char *type);
+
+	/*! \brief Callback for creating an object */
+	int (*create)(void *data, void *object);
+
+	/*! \brief Callback for retrieving an object using an id */
+	void *(*retrieve_id)(const struct ast_sorcery *sorcery, void *data, const char *type, const char *id);
+
+	/*! \brief Optional callback for retrieving an object using fields */
+	void *(*retrieve_fields)(const struct ast_sorcery *sorcery, void *data, const char *type, const struct ast_variable *fields);
+
+	/*! \brief Optional callback for retrieving multiple objects using some optional field criteria */
+	void (*retrieve_multiple)(const struct ast_sorcery *sorcery, void *data, const char *type, struct ao2_container *objects, const struct ast_variable *fields);
+
+	/*! \brief Callback for updating an object */
+	int (*update)(void *data, void *object);
+
+	/*! \brief Callback for deleting an object */
+	int (*delete)(void *data, void *object);
+
+	/*! \brief Callback for closing a wizard */
+	void (*close)(void *data);
+};
+
+/*! \brief Structure which contains details about a sorcery object */
+struct ast_sorcery_object_details {
+	/*! \brief Unique identifier of this object */
+	char id[AST_UUID_STR_LEN];
+
+	/*! \brief Type of object */
+	char type[MAX_OBJECT_TYPE];
+};
+
+/*! \brief Macro which must be used at the beginning of each sorcery capable object */
+#define SORCERY_OBJECT(details)                    \
+struct {                                           \
+	struct ast_sorcery_object_details details; \
+}                                                  \
+
+/*!
+ * \brief Initialize the sorcery API
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int ast_sorcery_init(void);
+
+/*!
+ * \brief Register a sorcery wizard
+ *
+ * \param interface Pointer to a wizard interface
+ * \param module Pointer to the module implementing the interface
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int __ast_sorcery_wizard_register(const struct ast_sorcery_wizard *interface, struct ast_module *module);
+
+/*!
+ * \brief See \ref __ast_sorcery_wizard_register()
+ */
+#define ast_sorcery_wizard_register(interface) __ast_sorcery_wizard_register(interface, ast_module_info ? ast_module_info->self : NULL)
+
+/*!
+ * \brief Unregister a sorcery wizard
+ *
+ * \param interface Pointer to the wizard interface
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int ast_sorcery_wizard_unregister(const struct ast_sorcery_wizard *interface);
+
+/*!
+ * \brief Open a new sorcery structure
+ *
+ * \retval non-NULL success
+ * \retval NULL if allocation failed
+ */
+struct ast_sorcery *ast_sorcery_open(void);
+
+/*!
+ * \brief Apply configured wizard mappings
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param name Name of the category to use within the configuration file, normally the module name
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int ast_sorcery_apply_config(struct ast_sorcery *sorcery, const char *name);
+
+/*!
+ * \brief Apply default object wizard mappings
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param type Type of object to apply to
+ * \param name Name of the wizard to use
+ * \param data Data to be passed to wizard
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ *
+ * \note This should be called *after* applying configuration sourced mappings
+ *
+ * \note Only a single default can exist per object type
+ */
+int ast_sorcery_apply_default(struct ast_sorcery *sorcery, const char *type, const char *name, const char *data);
+
+/*!
+ * \brief Register an object type
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param type Type of object
+ * \param alloc Required object allocation callback
+ * \param transform Optional transformation callback
+ * \param apply Optional object set apply callback
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int ast_sorcery_object_register(struct ast_sorcery *sorcery, const char *type, aco_type_item_alloc alloc, sorcery_transform_handler transform, sorcery_apply_handler apply);
+
+/*!
+ * \brief Register a field within an object
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param type Type of object
+ * \param name Name of the field
+ * \param default_val Default value of the field
+ * \param opt_type Option type
+ * \param flags Option type specific flags
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int __ast_sorcery_object_field_register(struct ast_sorcery *sorcery, const char *type, const char *name, const char *default_val, enum aco_option_type opt_type,
+                                        aco_option_handler config_handler, sorcery_field_handler sorcery_handler, unsigned int flags, size_t argc, ...);
+
+/*!
+ * \brief Register a field within an object
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param type Type of object
+ * \param name Name of the field
+ * \param default_val Default value of the field
+ * \param opt_type Option type
+ * \param flags Option type specific flags
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+#define ast_sorcery_object_field_register(sorcery, type, name, default_val, opt_type, flags, ...) \
+    __ast_sorcery_object_field_register(sorcery, type, name, default_val, opt_type, NULL, NULL, flags, VA_NARGS(__VA_ARGS__), __VA_ARGS__)
+
+/*!
+ * \brief Register a field within an object with custom handlers
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param type Type of object
+ * \param name Name of the field
+ * \param default_val Default value of the field
+ * \param config_handler Custom configuration handler
+ * \param sorcery_handler Custom sorcery handler
+ * \param flags Option type specific flags
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+#define ast_sorcery_object_field_register_custom(sorcery, type, name, default_val, config_handler, sorcery_handler, flags, ...) \
+    __ast_sorcery_object_field_register(sorcery, type, name, default_val, OPT_CUSTOM_T, config_handler, sorcery_handler, flags, VA_NARGS(__VA_ARGS__), __VA_ARGS__);
+
+/*!
+ * \brief Inform any wizards to load persistent objects
+ *
+ * \param sorcery Pointer to a sorcery structure
+ */
+void ast_sorcery_load(const struct ast_sorcery *sorcery);
+
+/*!
+ * \brief Inform any wizards to reload persistent objects
+ *
+ * \param sorcery Pointer to a sorcery structure
+ */
+void ast_sorcery_reload(const struct ast_sorcery *sorcery);
+
+/*!
+ * \brief Increase the reference count of a sorcery structure
+ *
+ * \param sorcery Pointer to a sorcery structure
+ */
+void ast_sorcery_ref(struct ast_sorcery *sorcery);
+
+/*!
+ * \brief Create an object set (KVP list) for an object
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param object Pointer to a sorcery object
+ *
+ * \retval non-NULL success
+ * \retval NULL if error occurred
+ *
+ * \note The returned ast_variable list must be destroyed using ast_variables_destroy
+ */
+struct ast_variable *ast_sorcery_objectset_create(const struct ast_sorcery *sorcery, const void *object);
+
+/*!
+ * \brief Apply an object set (KVP list) to an object
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param object Pointer to a sorcery object
+ * \param objectset Object set itself
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ *
+ * \note This operation is *not* atomic. If this fails it is possible for the object to be left with a partially
+ *       applied object set.
+ */
+int ast_sorcery_objectset_apply(const struct ast_sorcery *sorcery, void *object, struct ast_variable *objectset);
+
+/*!
+ * \brief Create a changeset given two object sets
+ *
+ * \param original Original object set
+ * \param modified Modified object set
+ * \param changes Pointer to hold any changes between the object sets
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ *
+ * \note The returned ast_variable list must be destroyed using ast_variables_destroy
+ */
+int ast_sorcery_changeset_create(const struct ast_variable *original, const struct ast_variable *modified, struct ast_variable **changes);
+
+/*!
+ * \brief Allocate an object
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param type Type of object to allocate
+ * \param id Optional unique identifier, if none is provided one will be generated
+ *
+ * \retval non-NULL success
+ * \retval NULL failure
+ */
+void *ast_sorcery_alloc(const struct ast_sorcery *sorcery, const char *type, const char *id);
+
+/*!
+ * \brief Create a copy of an object
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param object Existing object
+ *
+ * \retval non-NULL success
+ * \retval NULL failure
+ */
+void *ast_sorcery_copy(const struct ast_sorcery *sorcery, const void *object);
+
+/*!
+ * \brief Create a changeset of two objects
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param original Original object
+ * \param modified Modified object
+ * \param changes Pointer which will be populated with changes if any exist
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ *
+ * \note The returned ast_variable list must be destroyed using ast_variables_destroy
+ *
+ * \note While the objects must be of the same type they do not have to be the same object
+ */
+int ast_sorcery_diff(const struct ast_sorcery *sorcery, const void *original, const void *modified, struct ast_variable **changes);
+
+/*!
+ * \brief Create and potentially persist an object using an available wizard
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param object Pointer to a sorcery object
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int ast_sorcery_create(const struct ast_sorcery *sorcery, void *object);
+
+/*!
+ * \brief Retrieve an object using its unique identifier
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param type Type of object to retrieve
+ * \param id Unique object identifier
+ *
+ * \retval non-NULL if found
+ * \retval NULL if not found
+ */
+void *ast_sorcery_retrieve_by_id(const struct ast_sorcery *sorcery, const char *type, const char *id);
+
+/*!
+ * \brief Retrieve an object or multiple objects using specific fields
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param type Type of object to retrieve
+ * \param flags Flags to control behavior
+ * \param fields Optional jbject fields and values to match against
+ *
+ * \retval non-NULL if found
+ * \retval NULL if not found
+ *
+ * \note If the AST_RETRIEVE_FLAG_MULTIPLE flag is specified the returned value will be an
+ *       ao2_container that must be unreferenced after use.
+ *
+ * \note If the AST_RETRIEVE_FLAG_ALL flag is used you may omit fields to retrieve all objects
+ *       of the given type.
+ */
+void *ast_sorcery_retrieve_by_fields(const struct ast_sorcery *sorcery, const char *type, unsigned int flags, struct ast_variable *fields);
+
+/*!
+ * \brief Update an object
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param object Pointer to a sorcery object
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int ast_sorcery_update(const struct ast_sorcery *sorcery, void *object);
+
+/*!
+ * \brief Delete an object
+ *
+ * \param sorcery Pointer to a sorcery structure
+ * \param object Pointer to a sorcery object
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+int ast_sorcery_delete(const struct ast_sorcery *sorcery, void *object);
+
+/*!
+ * \brief Decrease the reference count of a sorcery structure
+ *
+ * \param sorcery Pointer to a sorcery structure
+ */
+void ast_sorcery_unref(struct ast_sorcery *sorcery);
+
+/*!
+ * \brief Get the unique identifier of a sorcery object
+ *
+ * \param object Pointer to a sorcery object
+ *
+ * \retval unique identifier
+ */
+const char *ast_sorcery_object_get_id(const void *object);
+
+/*!
+ * \brief Get the type of a sorcery object
+ *
+ * \param object Pointer to a sorcery object
+ *
+ * \retval type of object
+ */
+const char *ast_sorcery_object_get_type(const void *object);
+
+#if defined(__cplusplus) || defined(c_plusplus)
+}
+#endif
+
+#endif /* _ASTERISK_SORCERY_H */