/*-------------------------------------------------------------------------
 * C-Pluff, a plug-in framework for C
 * Copyright 2007 Johannes Lehtinen
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *-----------------------------------------------------------------------*/

/** @file
 * Internal data structures and declarations
 */

#ifndef INTERNAL_H_
#define INTERNAL_H_


/* ------------------------------------------------------------------------
 * Inclusions
 * ----------------------------------------------------------------------*/

#include "defines.h"
#include <assert.h>
#if defined(DLOPEN_POSIX)
#include <dlfcn.h>
#elif defined(DLOPEN_LIBTOOL)
#include <ltdl.h>
#endif
#include "../kazlib/list.h"
#include "../kazlib/hash.h"
#include "cpluff.h"
#ifdef CP_THREADS
#include "thread.h"
#endif
#include "shared.h"


#ifdef __cplusplus
extern "C" {
#endif //__cplusplus


/* ------------------------------------------------------------------------
 * Constants
 * ----------------------------------------------------------------------*/

/// Preliminarily OK 
#define CP_OK_PRELIMINARY (-1)

/// Callback function logger function
#define CPI_CF_LOGGER 1

/// Callback function plug-in listener function
#define CPI_CF_LISTENER 2

/// Callback function start function
#define CPI_CF_START 4

/// Callback function stop function
#define CPI_CF_STOP 8

/// Bitmask corresponding to any callback function
#define CPI_CF_ANY (~0)

/// Logging limit for no logging
#define CP_LOG_NONE 1000

/// Plugin descriptor's default file name
#define CP_PLUGIN_DESCRIPTOR "plugin.xml"

/// Plugin descriptor's default root xml element
#define CP_PLUGIN_ROOT_ELEMENT "plugin"


/* ------------------------------------------------------------------------
 * Macros
 * ----------------------------------------------------------------------*/

#if defined(DLOPEN_POSIX)
#define DLHANDLE void *
#define DLOPEN(name) dlopen((name), RTLD_LAZY | RTLD_GLOBAL)
#define DLSYM(handle, symbol) dlsym((handle), (symbol))
#define DLCLOSE(handle) dlclose(handle)
#define DLERROR() dlerror()
#elif defined(DLOPEN_LIBTOOL)
#define DLHANDLE lt_dlhandle
#define DLOPEN(name) lt_dlopen(name)
#define DLSYM(handle, symbol) lt_dlsym((handle), (symbol))
#define DLCLOSE(handle) lt_dlclose(handle)
#define DLERROR() lt_dlerror()
#endif


/**
 * Checks that the specified function argument is not NULL.
 * Otherwise, reports a fatal error.
 * 
 * @param arg the argument
 */
#define CHECK_NOT_NULL(arg) do { if ((arg) == NULL) cpi_fatal_null_arg(#arg, __func__); } while (0)


/* ------------------------------------------------------------------------
 * Data types
 * ----------------------------------------------------------------------*/

typedef struct cp_plugin_t cp_plugin_t;
typedef struct cp_plugin_env_t cp_plugin_env_t;

// Plug-in context
struct cp_context_t {
	
	/// The associated plug-in instance or NULL for the main program
	cp_plugin_t *plugin;
	
	/// The associated plug-in environment
	cp_plugin_env_t *env;

	/// Information about resolved symbols or NULL if not initialized
	hash_t *resolved_symbols;

	/// Information about symbol providing plugins or NULL if not initialized
	hash_t *symbol_providers;
	
};

// Plug-in environment
struct cp_plugin_env_t {

#if defined(CP_THREADS)

	/// Mutex for accessing this plug-in environment.
	/// This mutex is signaled when a run function returns.
	cpi_mutex_t *mutex;
	
#elif !defined(NDEBUG)
	int locked;
#endif

	/// Number of startup arguments
	int argc;
	
	/// An array of startup arguments
	char **argv;
	
	/// Plugin descriptor file name
	const char *plugin_descriptor_name;

	/// Plugin descriptor's XML root element
	const char *plugin_descriptor_root_element;

	/// Installed plug-in listeners 
	list_t *plugin_listeners;
	
	/// Registered loggers
	list_t *loggers;

	/// Minimum logger selection severity
	int log_min_severity;

    /// The implicit local plug-in loader, or NULL if none
    cp_plugin_loader_t *local_loader;

	/// Maps registered plug-in loaders to the lists of plug-in identifiers
	hash_t *loaders_to_plugins;
	
	/// Map of in-use reference counted information objects
	hash_t *infos;

	/// Maps plug-in identifiers to plug-in state structures 
	hash_t *plugins;

	/// List of started plug-ins in the order they were started 
	list_t *started_plugins;

	/// Maps extension point names to installed extension points
	hash_t *ext_points;
	
	/// Maps extension point names to installed extensions
	hash_t *extensions;
	
	/// FIFO queue of run functions, currently running functions at front
	list_t *run_funcs;
	
	/// First waiting run function, or NULL if none
	lnode_t *run_wait;

	/// Is logger currently being invoked
	int in_logger_invocation;

	/// Whether currently in event listener invocation
	int in_event_listener_invocation;
	
	/// Whether currently in start function invocation
	int in_start_func_invocation;
	
	/// Whether currently in stop function invocation
	int in_stop_func_invocation;
	
	/// Whether currently in create function invocation
	int in_create_func_invocation;
	
	/// Whether currently in destroy function invocation
	int in_destroy_func_invocation;
	
	/// Whether currently in plug-in loader function invocation
	int in_plugin_loader_invocation;
	
};

// Plug-in instance
struct cp_plugin_t {
	
	/// The enclosing context or NULL if none exists
	cp_context_t *context;
	
	/// Plug-in information 
	cp_plugin_info_t *plugin;
	
	/// Plug-in loader, or NULL if none
	cp_plugin_loader_t *loader;
	
	/// The current state of the plug-in 
	cp_plugin_state_t state;
	
	/// The set of imported plug-ins, or NULL if not resolved 
	list_t *imported;
	
	/// The set of plug-ins importing this plug-in 
	list_t *importing;
	
	/// The runtime library handle, or NULL if not resolved 
	DLHANDLE runtime_lib;
	
	/// Plug-in runtime function information, or NULL if not resolved
	cp_plugin_runtime_t *runtime_funcs;

	/// Plug-in instance data or NULL if instance does not exist
	void *plugin_data;
	
	/// Context specific symbols defined by the plug-in
	hash_t *defined_symbols;
	
	/// Used by recursive operations: has this plug-in been processed already
	int processed;
	
};


/**
 * Deallocates a reference counted resource when the reference count drops
 * to zero. The plug-in context is locked on call to the function.
 * 
 * @param ctx the associated plug-in context
 * @param resource the resource
 */
typedef void (*cpi_dealloc_func_t)(cp_context_t *ctx, void *resource);

typedef struct cpi_plugin_event_t cpi_plugin_event_t;

/// Plug-in event information
struct cpi_plugin_event_t {
	
	/// The affect plug-in
	const char *plugin_id;
	
	/// Old state
	cp_plugin_state_t old_state;
	
	/// New state
	cp_plugin_state_t new_state;
};


/* ------------------------------------------------------------------------
 * Function declarations
 * ----------------------------------------------------------------------*/


// Locking data structures for exclusive access 

#if defined(CP_THREADS) || !defined(NDEBUG)

/**
 * Acquires exclusive access to the framework. Thread having the framework
 * lock must not acquire plug-in context lock (it is ok to retain a previously
 * acquired plug-in context lock).
 */
CP_HIDDEN void cpi_lock_framework(void);

/**
 * Releases exclusive access to the framework.
 */
CP_HIDDEN void cpi_unlock_framework(void);

/**
 * Acquires exclusive access to a plug-in context and the associated
 * plug-in environment.
 * 
 * @param context the plug-in context
 */
CP_HIDDEN void cpi_lock_context(cp_context_t *context) CP_GCC_NONNULL(1);

/**
 * Releases exclusive access to a plug-in context.
 * 
 * @param context the plug-in context
 */
CP_HIDDEN void cpi_unlock_context(cp_context_t *context) CP_GCC_NONNULL(1);

/**
 * Waits until the specified plug-in context is signalled.
 * 
 * @param context the plug-in context
 */
CP_HIDDEN void cpi_wait_context(cp_context_t *context) CP_GCC_NONNULL(1);

/**
 * Signals the specified plug-in context.
 * 
 * @param context the plug-in context
 */
CP_HIDDEN void cpi_signal_context(cp_context_t *context) CP_GCC_NONNULL(1);

#else
#define cpi_lock_context(dummy) do {} while (0)
#define cpi_unlock_context(dummy) do {} while (0)
#define cpi_wait_context(dummy) do {} while (0)
#define cpi_signal_context(dummy) do {} while (0)
#define cpi_lock_framework() do {} while(0)
#define cpi_unlock_framework() do {} while(0)
#endif

/** 
 * @def cpi_is_context_locked
 * 
 * Returns whether the context is locked. This is intended to be used in
 * assertions only and it is not defined if debugging is not enabled.
 */

#ifndef NDEBUG
#ifdef CP_THREADS
#define cpi_is_context_locked(ctx) cpi_is_mutex_locked((ctx)->env->mutex)
#else
#define cpi_is_context_locked(ctx) ((ctx)->env->locked)
#endif
#endif


// Logging

/**
 * Logs a message. Calls dgettext for @a msg to localize it before delivering
 * it to loggers. The caller must have locked the context. This
 * function logs the message unconditionally. Use convenience macros
 * @ref cpi_error, @ref cpi_warn, @ref cpi_info and @ref cpi_debug
 * to log based on the minimum severity level logged.
 * 
 * @param ctx the related plug-in context
 * @param severity the severity of the message
 * @param msg the localized message
 */
CP_HIDDEN void cpi_log(cp_context_t *ctx, cp_log_severity_t severity, const char *msg) CP_GCC_NONNULL(1, 3);

/**
 * Formats and logs a message. Calls dgettext for @a msg to localize it before
 * formatting the message. The caller must have locked the context. This
 * function logs the message unconditionally. Use convenience macros
 * @ref cpi_errorf, @ref cpi_warnf, @ref cpi_infof and @ref cpi_debugf
 * to log based on the minimum severity level logged. 
 * 
 * @param ctx the related plug-in context
 * @param severity the severity of the message
 * @param msg the localized message format
 * @param ... the message parameters
 */
CP_HIDDEN void cpi_logf(cp_context_t *ctx, cp_log_severity_t severity, const char *msg, ...) CP_GCC_PRINTF(3, 4) CP_GCC_NONNULL(1, 3);

/**
 * Returns whether the messages of the specified severity level are
 * being logged for the specified context. The caller must have locked the context.
 * 
 * @param ctx the plug-in context
 * @param severity the severity
 * @return whether the messages of the specified severity level are logged
 */
#define cpi_is_logged(context, severity) (assert(cpi_is_context_locked(context)), (severity) >= (context)->env->log_min_severity)

// Convenience macros for efficient logging
#define cpi_log_cond(ctx, level, msg) do { if (cpi_is_logged((ctx), (level))) cpi_log((ctx), (level), (msg)); } while (0)
#define cpi_logf_cond(ctx, level, msg, ...) do { if (cpi_is_logged((ctx), (level))) cpi_logf((ctx), (level), (msg), __VA_ARGS__); } while (0)
#define cpi_error(ctx, msg) cpi_log_cond((ctx), CP_LOG_ERROR, (msg))
#define cpi_errorf(ctx, msg, ...) cpi_logf_cond((ctx), CP_LOG_ERROR, (msg), __VA_ARGS__)
#define cpi_warn(ctx, msg) cpi_log_cond((ctx), CP_LOG_WARNING, (msg))
#define cpi_warnf(ctx, msg, ...) cpi_logf_cond((ctx), CP_LOG_WARNING, (msg), __VA_ARGS__)
#define cpi_info(ctx, msg) cpi_log_cond((ctx), CP_LOG_INFO, (msg))
#define cpi_infof(ctx, msg, ...) cpi_logf_cond((ctx), CP_LOG_INFO, (msg), __VA_ARGS__)
#define cpi_debug(ctx, msg) cpi_log_cond((ctx), CP_LOG_DEBUG, (msg))
#define cpi_debugf(ctx, msg, ...) cpi_logf_cond((ctx), CP_LOG_DEBUG, (msg), __VA_ARGS__)

/**
 * Unregisters loggers in the specified logger list. Either unregisters all
 * loggers or only loggers installed by the specified plug-in.
 * 
 * @param loggers the logger list
 * @param plugin the plug-in whose loggers to unregister or NULL for all
 */
CP_HIDDEN void cpi_unregister_loggers(list_t *loggers, cp_plugin_t *plugin) CP_GCC_NONNULL(1);

/**
 * Unregisters plug-in listeners in the specified list. Either unregisters all
 * listeners or only listeners installed by the specified plug-in.
 * 
 * @param listeners the listener list
 * @param plugin the plug-in whose listeners to unregister or NULL for all
 */
CP_HIDDEN void cpi_unregister_plisteners(list_t *listeners, cp_plugin_t *plugin) CP_GCC_NONNULL(1);

/**
 * Returns the owner name for a context.
 * 
 * @param ctx the context
 * @param name the location where the name of the owner is to be stored
 * @param size maximum size of the owner string, including the terminating zero
 * @return the pointer passed in as @a name
 */
CP_HIDDEN char *cpi_context_owner(cp_context_t *ctx, char *name, size_t size) CP_GCC_NONNULL(1);

/**
 * Reports a fatal NULL argument to an API function.
 * 
 * @param arg the argument name
 * @param func the API function name
 */
CP_HIDDEN void cpi_fatal_null_arg(const char *arg, const char *func) CP_GCC_NORETURN CP_GCC_NONNULL(1, 2);

/**
 * Checks that we are currently not in a specific callback function invocation.
 * Otherwise, reports a fatal error. The caller must have locked the context
 * before calling this function.
 * 
 * @param ctx the associated plug-in context
 * @param funcmask the bitmask of disallowed callback functions
 * @param func the current plug-in framework function
 */
CP_HIDDEN void cpi_check_invocation(cp_context_t *ctx, int funcmask, const char *func) CP_GCC_NONNULL(1, 3);


// Context management

/**
 * Allocates a new plug-in context.
 * 
 * @param plugin the associated plug-in or NULL for the client program
 * @param env the associated plug-in environment
 * @param status a pointer to the location where the status code is to be stored
 * @return the newly allocated context or NULL on failure
 */
CP_HIDDEN cp_context_t * cpi_new_context(cp_plugin_t *plugin, cp_plugin_env_t *env, cp_status_t *status) CP_GCC_NONNULL(2, 3);

/**
 * Frees the resources associated with a plug-in context. Also frees the
 * associated plug-in environment if the context is a client program plug-in
 * context.
 * 
 * @param context the plug-in context to free
 */
CP_HIDDEN void cpi_free_context(cp_context_t *context) CP_GCC_NONNULL(1);

/**
 * Destroys all contexts and releases the context list resources.
 */
CP_HIDDEN void cpi_destroy_all_contexts(void);


// Delivering plug-in events 

/**
 * Delivers a plug-in event to registered event listeners.
 * 
 * @param context the plug-in context
 * @param event the plug-in event
 */
CP_HIDDEN void cpi_deliver_event(cp_context_t *context, const cpi_plugin_event_t *event) CP_GCC_NONNULL(1, 2);


// Plug-in management

/**
 * Installs the specified plug-in.
 *
 * @param context the plug-in context
 * @param plugin the plug-in information structure
 * @param loader the associated plug-in loader or NULL for none
 * @return @ref CP_OK (zero) on success or an error code on failure
 */
CP_HIDDEN cp_status_t cpi_install_plugin(cp_context_t *context, cp_plugin_info_t *plugin, cp_plugin_loader_t *loader) CP_GCC_NONNULL(1, 2);

/**
 * Frees any resources allocated for a plug-in description.
 * 
 * @param plugin the plug-in to be freed
 */
CP_HIDDEN void cpi_free_plugin(cp_plugin_info_t *plugin) CP_GCC_NONNULL(1);

/**
 * Starts the specified plug-in and its dependencies.
 * 
 * @param context the plug-in context
 * @param plugin the plug-in
 * @return @ref CP_OK (zero) on success or an error code on failure
 */
CP_HIDDEN cp_status_t cpi_start_plugin(cp_context_t *context, cp_plugin_t *plugin) CP_GCC_NONNULL(1, 2);


// Dynamic resource management

/**
 * Registers a new reference counted information object.
 * Initializes the reference count to 1. The object is released and
 * deallocated using the specified deallocation function @a df when its
 * reference count becomes zero. Reference count is incresed by
 * ::cpi_use_info and decreased by ::cp_release_info. The caller must have
 * locked the plug-in context.
 * 
 * @param ctx the associated plug-in context
 * @param res the resource
 * @param df the deallocation function
 * @return @ref CP_OK (zero) on success or an error code on failure
 */
CP_HIDDEN cp_status_t cpi_register_info(cp_context_t *ctx, void *res, cpi_dealloc_func_t df) CP_GCC_NONNULL(1, 2, 3);

/**
 * Increases the reference count for the specified information object.
 * The caller must have locked the plug-in context.
 * 
 * @param ctx the plug-in context
 * @param res the resource
 */
CP_HIDDEN void cpi_use_info(cp_context_t *ctx, void *res) CP_GCC_NONNULL(1, 2);

/**
 * Decreases the reference count for the specified information object.
 * The caller must have locked the plug-in context.
 * 
 * @param ctx the plug-in context
 * @param res the resource
 */
CP_HIDDEN void cpi_release_info(cp_context_t *ctx, void *res) CP_GCC_NONNULL(1, 2);

/**
 * Checks for remaining information objects in the specified plug-in context.
 * Does not destroy the infos hash.
 * 
 * @param ctx the plug-in context
 */
CP_HIDDEN void cpi_release_infos(cp_context_t *ctx) CP_GCC_NONNULL(1);


// Serialized execution

/**
 * Waits for all the run functions registered by the specified plug-in to
 * return and then unregisters them. The caller must have locked the
 * associated context.
 * 
 * @param plugin the plug-in to be stopped
 */
CP_HIDDEN void cpi_stop_plugin_run(cp_plugin_t *plugin) CP_GCC_NONNULL(1);


#ifdef __cplusplus
}
#endif //__cplusplus

#endif /*INTERNAL_H_*/