NodeSpace.h

Legacy: This article describes a concept that has been superseded in the course of ongoing development on the Organic Design wiki. Please do not develop this any further or base work on this concept, this is only useful for a historic record of work done. You may find a link to the currently used concept or function in this article, if not you can contact the author to find out what has taken the place of this legacy item.

// [[[[http://www.organicdesign.co.nz/peerd|peerd]]]] - nodal p2p wiki daemon
// This article and all its includes are licenced under LGPL
// GPL: [[[[http://www.gnu.org/copyleft/lesser.html]]]]
// SRC: [[[[http://www.organicdesign.co.nz/nodeSpace.c]]]]
// included in [[[[http://www.organicdesign.co.nz/category:peerd/files/C|peerd]]]][[[[http://www.organicdesign.co.nz/peerd.c|/peerd.c]]]]

// node: a type for referring to nodes
typedef int node;

// code is a variable of type pointer-to-function
typedef void (codeType)();
codeType *code;

// constants defined in [[[[peerd.c]]]]
// - nodal constants
// - this and parent

// stateless
node nodeSESSION;
node nodeSTREAMS;

// function ref
node nodeEVENTS;
node nodeIO;
node nodeSERVER;
node nodeDESKTOP;
node nodeRENDER;

// pointer to struct
node nodeSTREAM;
node nodeSPRITE;
node nodeEVENT;

// Prototypes
node nodeGetValue(node subject,node key);
node nodeSetValue(node subject,node key,node value);
node nodeInsertKey(node subject,node key);
node nodeRemoveKey(node subject,node key);
node nodeLoopInsert(node subject,node insert);
node nodeLoopRemove(node subject,node remove);
node nodeLoopRotate(node subject);
node nodeTraverse(node subject,node *path);
void **nodeState(node subject,node key);
void nodeInit();
void nodeExit();
void ifExit();
void nodeReduce();


// ----------------------------------------------------------------------------------------- //
// nodeSpace.c

// set nodal value of node/path
node nodeGetValue(node subject,node key) {
	// todo: if subject/nodeGETVAL...
	return listGetValue(listTraverse(subject,key));
	}

node nodeSetValue(node subject,node key,node value) {
	// todo: onChange
	return listSetValue(listTraverse(subject,key),value);
	}

// Returns a newly created node
node nodeInsert() {
	return listInsert();
	}

// Returns newly created node
// - this is just traverse() but with an event raised
node nodeInsertKey(node subject,node key) {
	// todo: hook in nodeSTART
	return listTraverse(subject,key);
	}

// Returns the node that was removed
node nodeRemoveKey(node subject,node key) {
	// todo: hook in nodeSTOP
	node i = listTraverse(subject,key);
	// todo: delete
	return i;
	}

// Returns the inserted node as the new loop pointer
// - this allows it to act as a stack if nodeLOOP (current-loop-node) is updated with returned node
// - either can be 0 on entry (for new loop and/or new node)
// todo: update nodePARENT of inserted node
node nodeLoopInsert(node subject,node insert) {
	node focus = nodeGetValue(subject,0);
	if (insert == 0) insert = nodeInsert();
	if (focus) {
		// Insert into existing [[[[loop]]]] ([[[[focus]]]] remains unchanged)
		node next = nodeGetValue(focus,nodeNEXT);
		nodeSetValue(insert,nodeNEXT,next);
		nodeSetValue(insert,nodePREV,focus);
		nodeSetValue(next,nodePREV,insert);
		nodeSetValue(focus,nodeNEXT,insert);
		}
	else {
		// No existing [[[[loop]]]], make new node into a single item loop
		nodeSetValue(subject,0,insert);
		nodeSetValue(insert,nodeNEXT,insert);
		nodeSetValue(insert,nodePREV,insert);
		}
	nodeSetValue(insert,nodePARENT,subject);
	return insert;
	}

// Removes a node from the subject's [[[[loop]]]]
// - if remove parameter is 0, the [[[[focus]]]] node is removed and next becomes the new focus
// - the removed item is returned not the focus
// - the removed node's parent is set to 0
node nodeLoopRemove(node subject,node remove) {
node n = remove;
	node focus = nodeGetValue(subject,0);
	if (focus) {
		if (remove == 0) remove = focus;
		node prev = nodeGetValue(remove,nodePREV);
		node next = nodeGetValue(remove,nodeNEXT);
		nodeSetValue(next,nodePREV,prev);
		nodeSetValue(prev,nodeNEXT,next);
		if (next == remove) next = 0;
		if (remove == focus) focus = nodeSetValue(subject,0,next);
		nodeSetValue(remove,nodePARENT,0);
		}
	return remove;
	}

// Rotates the subject node's [[[[loop]]]] and returning the last [[[[focus]]]]
node nodeLoopRotate(node subject) {
	node focus = nodeGetValue(subject,0);
	if (focus) nodeSetValue(subject,0,nodeGetValue(focus,nodeNEXT));
	return focus;
	}

// not used yet - use array-of-node path?
node nodeTraverse(node subject,node *path) {
	}

// Treat an association value as a pointer index
void **nodeState(node subject,node key) {
	int index = nodeGetValue(subject,key);
	if (index == 0) nodeSetValue(subject,key,index = insertPointer(NULL));
	return pointer(index);
	}

// Clean up all the mess and exit
// - add exit functions here for any includes requiring cleanup before exit
void nodeExit() {
	logAdd("Gracefully exiting.");
	ifExit();
	ioExit();
	listExit();
	exit(EXIT_SUCCESS);
	}


// Set up initial nodal structure
// - todo: this structure should be read from [[[[nodeSpace.txt]]]]
// - use [[[[io.c]]]] for reading content from wiki if url/file
char *serialise(node);
void deserialise(char*);
void nodeInit() {

	if (file) {

		// todo: load from file and deserialise

		}
	else {
		// no file specified in command-line args, use default inline text
		deserialise("\
			*[[0|root]]\
			*[[1000|io]];[[1001|session]];\
			*[[io]]\
			*[[1002|server]];[[1003|streams]];\
			*[[1004|stream]]\
			*[[session]]\
			*[[1006|desktop]];\
			*[[1007|sprite]]\
			*[[render]]\
			");
		}
	nodeIO        = trieGetValue("io");        logAdd("nodeIO = %d",nodeIO);
	nodeSESSION   = trieGetValue("session");   logAdd("nodeSESSION = %d",nodeSESSION);
	nodeSERVER    = trieGetValue("server");    logAdd("nodeSERVER = %d",nodeSERVER);
	nodeSTREAMS   = trieGetValue("streams");   logAdd("nodeSTREAMS = %d",nodeSTREAMS);
	nodeSTREAM    = trieGetValue("stream");    logAdd("nodeSTREAM = %d",nodeSTREAM);
	nodeDESKTOP   = trieGetValue("desktop");   logAdd("nodeDESKTOP = %d",nodeDESKTOP);
	nodeSPRITE    = trieGetValue("sprite");    logAdd("nodeSPRITE = %d",nodeSPRITE);
	nodeRENDER    = trieGetValue("render");    logAdd("nodeRENDER = %d",nodeRENDER);

	}

// Moves "this" to node's [[[[focus]]]] if exists then rotates [[[[loop]]]] and executes/reduces the focus item
void nodeReduce() {
	grandpa = parent;
	if (this = nodeLoopRotate(parent = this)) {       // Move "this" to the [[[[focus]]]] in the node's loop and rotate
		nodeSetValue(this,nodePARENT,parent);         // Update the [[[[parent]]]] association
		if (code = *nodeState(this,nodeCODE)) code(); // [[[[nodeCODE]]]] value is a pointer-index, execute as function-reference if non-zero
		}
	}