env_universal_common.h

#ifndef FISH_ENV_UNIVERSAL_COMMON_H
#define FISH_ENV_UNIVERSAL_COMMON_H

#include <wchar.h>
#include <queue>
#include "util.h"

/**
   The set command
*/
#define SET_STR L"SET"

/**
   The set_export command
*/
#define SET_EXPORT_STR L"SET_EXPORT"

/**
   The erase command
*/
#define ERASE_STR L"ERASE"

/**
   The barrier command
*/
#define BARRIER_STR L"BARRIER"

/**
   The barrier_reply command
*/
#define BARRIER_REPLY_STR L"BARRIER_REPLY"


/**
   The filename to use for univeral variables. The username is appended
*/
#define SOCK_FILENAME "fishd.socket."

/**
   The different types of commands that can be sent between client/server
*/
enum
{
	SET,
	SET_EXPORT,
	ERASE,
	BARRIER,
	BARRIER_REPLY,
}
	;

/**
   The size of the buffer used for reading from the socket
*/
#define ENV_UNIVERSAL_BUFFER_SIZE 1024

/**
   A struct representing a message to be sent between client and server
*/
typedef struct 
{
	/**
	   Number of queues that contain this message. Once this reaches zero, the message should be deleted
	*/
	int count;
	/**
	   Message body. The message must be allocated using enough memory to actually contain the message.
	*/
	char body[1];
}
	message_t;

typedef std::queue<message_t *> message_queue_t;

/**
   This struct represents a connection between a universal variable server/client
*/
typedef struct connection
{
	/**
	   The file descriptor this socket lives on
	*/
	int fd;
	/**
	   Queue of onsent messages
	*/
    message_queue_t *unsent;
	/**
	   Set to one when this connection should be killed
	*/
	int killme;
	/**
	   The input string. Input from the socket goes here. When a
	   newline is encountered, the buffer is parsed and cleared.
	*/
	std::vector<char> input;
	
	/**
	   The read buffer. 
	*/
	char buffer[ENV_UNIVERSAL_BUFFER_SIZE];

	/**
	   Number of bytes that have already been consumed.
	*/
	int buffer_consumed;
	
	/**
	   Number of bytes that have been read into the buffer. 
	*/
	int buffer_used;
	

	/**
	   Link to the next connection
	*/
	struct connection *next;
}
	connection_t;

/**
   Read all available messages on this connection
*/
void read_message( connection_t * );

/**
   Send as many messages as possible without blocking to the connection
*/
void try_send_all( connection_t *c );

/**
   Create a messge with the specified properties
*/
message_t *create_message( int type, const wchar_t *key, const wchar_t *val );

/**
   Init the library
*/
void env_universal_common_init(void (*cb)(int type, const wchar_t *key, const wchar_t *val ) );

/**
   Destroy library data
*/
void env_universal_common_destroy();

/**
   Add all variable names to the specified list

   This function operate agains the local copy of all universal
   variables, it does not communicate with any other process.
*/
void env_universal_common_get_names( wcstring_list_t &lst,
									 int show_exported,
									 int show_unexported );

/**
   Perform the specified variable assignment.

   This function operate agains the local copy of all universal
   variables, it does not communicate with any other process.

   Do not call this function. Create a message to do it. This function
   is only to be used when fishd is dead.
*/
void env_universal_common_set( const wchar_t *key, const wchar_t *val, int exportv );

/**
   Remove the specified variable. 

   This function operate agains the local copy of all universal
   variables, it does not communicate with any other process.

   Do not call this function. Create a message to do it. This function
   is only to be used when fishd is dead.
*/
void env_universal_common_remove( const wcstring &key );

/**
   Get the value of the variable with the specified name

   This function operate agains the local copy of all universal
   variables, it does not communicate with any other process.
*/
wchar_t *env_universal_common_get( const wcstring &name );

/**
   Get the export flag of the variable with the specified
   name. Returns 0 if the variable doesn't exist.

   This function operate agains the local copy of all universal
   variables, it does not communicate with any other process.
*/
int env_universal_common_get_export( const wcstring &name );

/**
   Add messages about all existing variables to the specified connection
*/
void enqueue_all( connection_t *c );

/**
   Fill in the specified connection_t struct. Use the specified file
   descriptor for communication.
*/
void connection_init( connection_t *c, int fd );

/**
   Close and destroy the specified connection struct. This frees
   allstructures allocated by the connection, such as ques of unsent
   messages.
*/
void connection_destroy( connection_t *c);

#endif