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Commit d5e55b69 authored by mcmlxxix's avatar mcmlxxix
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remove clone function (no longer needed), reject root object requests, no... 

remove clone function (no longer needed), reject root object requests, no longer self-instantiate, bundle LOCK/operation/UNLOCK requests when a lock is specified on an operation
parent 396d041c
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with 93 additions and 102 deletions
exec/load/json-db.js
+ 93
− 102
View file @ d5e55b69
......@@ -27,12 +27,25 @@
*/
if(!this.Database) {
Database = new (function() {
function JSONdb (fileName) {
this.VERSION = "$Revision$".split(' ')[1];
/* database storage file */
if(fileName)
this.file=new File(fileName);
else
this.file=undefined;
/* master database object */
this.data={};
/* database record subscription and locking object */
this.shadow={};
/* queued array of data requests (get/put/create/delete) */
this.queue=[];
/* database settings */
this.settings={
/* record lock constants, incremental (do not change the order or value) */
......@@ -57,76 +70,6 @@ Database = new (function() {
ERROR_DUPLICATE_LOCK:5
};
/**************************** database objects *****************************/
/* locking object generated by Database.lock() method
contains the type of lock requested, and the time at which the request came in
TODO: possibly "expire" unfulfilled lock requests after a certain period */
function Lock(lock_type,timestamp) {
this.type=lock_type;
this.timestamp=timestamp;
}
/* error object containing a description of the error */
function Error(error_num,error_desc) {
this.operation="ERROR";
this.error_num=error_num;
this.error_desc=error_desc;
}
/* shadow properties generated by composite_sketch()
contains a relative object's subscribers, locks, and child name */
function Shadow() {
this._lock=[];
this._lock_pending=false;
this._subscribers=[];
}
/* record object returned by identify_remains()
contains the requested object, its shadow object,
the prevailing lock state of that object (affected by parents/children),
and a list of subscribers associated with that object or its parents */
function Record(data,shadow,parent_name,child_name,info) {
this.data=data;
this.shadow=shadow;
this.parent_name=parent_name;
this.child_name=child_name;
this.info=info;
}
/* request object generated by Database.queue() method
contains the requested object parent, the specific child property requested,
data (in the case of a PUT operation ) */
function Request(client,operation,parent_name,child_name,data) {
this.client=client;
this.operation=operation;
this.parent_name=parent_name;
this.child_name=child_name;
this.data=data;
}
/* in the event of a corrupt JSON object or database problem,
it would be beneficial to be able to single-out the affected
module for correction, rather than destroy the entire database
it would also allow for a much simpler mechanism for removing
games you no longer wish to host (simply delete the db file and edit your service inis) */
/*************************** database data ******************************/
/* database storage file */
if(argv[0])
this.file=new File(argv[0]);
else
this.file=undefined;
/* master database object */
this.data={};
/* database record subscription and locking object */
this.shadow={};
/* queued array of data requests (get/put/create/delete) */
this.queue=[];
/*************************** database methods ****************************/
/* subscribe a client to an object */
this.subscribe = function(client,record) {
......@@ -211,7 +154,7 @@ Database = new (function() {
if(client_lock) {
/* if this was a write lock, send an update to all record subscribers */
if(client_lock.type == this.settings.LOCK_WRITE)
send_updates(record);
send_updates(client,record);
delete record.shadow[record.child_name]._lock[client.id];
return true;
}
......@@ -229,8 +172,7 @@ Database = new (function() {
this.read = function(client,record) {
/* if this client has this record locked, read */
if(record.info.lock[client.id]) {
var data = clone(record.data[record.child_name]);
send_packet(client,data,"RESPONSE");
send_packet(client,record.data[record.child_name],"RESPONSE");
return true;
}
/* if there is no lock for this client, error */
......@@ -298,24 +240,33 @@ Database = new (function() {
var parent_name = query.location.substring(0,query.location.lastIndexOf("."));
/* store the child name */
var child_name = query.location.substr(query.location.lastIndexOf(".")+1);
/* if the data request is invalid or empty, return an error */
if(!parent_name || !child_name) {
this.error(client,this.settings.ERROR_INVALID_REQUEST);
return false;
}
/* temporary array for queue additions */
var q=[];
/* if an operation is requested */
if(query.operation !== undefined) {
request = new Request(client,query.operation,parent_name,child_name,query.data);
/* push this query into a queue to be processed at the next response cycle (this.cycle()) */;
q.push(request);
}
/* if there is an attached lock operation, process accordingly */
if(query.lock !== undefined) {
request = new Request(client,"LOCK",parent_name,child_name,query.lock);
/* if this is a read or write lock, put it ahead of the operation in the request queue */
if(query.lock == this.settings.LOCK_UNLOCK)
q.unshift(request);
/* if this is an unlock, process it after the operation in the request queue */
else if(query.lock == this.settings.LOCK_READ || query.lock == this.settings.LOCK_WRITE)
q.push(request);
/* put lock ahead of the operation in request queue */
q.unshift(new Request(
client,"LOCK",parent_name,child_name,query.lock
));
/* put unlock after the operation in the request queue */
q.push(new Request(
client,"LOCK",parent_name,child_name,this.settings.LOCK_UNLOCK
));
}
/* add the temporary queue to the main queue */
this.queue=this.queue.concat(q);
......@@ -413,7 +364,11 @@ Database = new (function() {
var result=false;
/* locate the requested record within the database */
var record=identify_remains.call(this,request.client,request.parent_name,request.child_name);
var record=identify_remains.call(
this,request.client,request.parent_name,request.child_name
);
log("r: " + record.data.toSource());
if(!record) {
log(LOG_DEBUG,"db: bad request removed from queue");
......@@ -464,6 +419,53 @@ Database = new (function() {
}
};
/**************************** database objects *****************************/
/* locking object generated by Database.lock() method
contains the type of lock requested, and the time at which the request came in
TODO: possibly "expire" unfulfilled lock requests after a certain period */
function Lock(lock_type,timestamp) {
this.type=lock_type;
this.timestamp=timestamp;
}
/* error object containing a description of the error */
function Error(error_num,error_desc) {
this.operation="ERROR";
this.error_num=error_num;
this.error_desc=error_desc;
}
/* shadow properties generated by composite_sketch()
contains a relative object's subscribers, locks, and child name */
function Shadow() {
this._lock=[];
this._lock_pending=false;
this._subscribers=[];
}
/* record object returned by identify_remains()
contains the requested object, its shadow object,
the prevailing lock state of that object (affected by parents/children),
and a list of subscribers associated with that object or its parents */
function Record(data,shadow,parent_name,child_name,info) {
this.data=data;
this.shadow=shadow;
this.parent_name=parent_name;
this.child_name=child_name;
this.info=info;
}
/* request object generated by Database.queue() method
contains the requested object parent, the specific child property requested,
data (in the case of a PUT operation ) */
function Request(client,operation,parent_name,child_name,data) {
this.client=client;
this.operation=operation;
this.parent_name=parent_name;
this.child_name=child_name;
this.data=data;
}
/*************************** database functions ****************************/
/* traverse object and create a shadow copy of the object structure
for record locking and subscribers, and create location names for database objects */
......@@ -490,12 +492,6 @@ Database = new (function() {
function identify_remains(client,parent_name,child_name) {
var p=parent_name.split(/\./);
/* if the data request is invalid or empty, return an error */
if(!p) {
this.error(client,this.settings.ERROR_INVALID_REQUEST);
return false;
}
var data=this.data;
var shadow=this.shadow;
var info={
......@@ -560,12 +556,6 @@ Database = new (function() {
}
}
/* make a copy of an object to avoid modifying the original */
function clone(obj) {
var newobj=eval(obj.toSource());
return newobj;
}
/* return the prevailing lock type and pending lock status for an object */
function investigate(shadow, info) {
/* if we havent found a write locked record yet, keep searching */
......@@ -596,8 +586,11 @@ Database = new (function() {
}
/* send updates of this object to all subscribers */
function send_updates(record) {
function send_updates(client,record) {
for each(var c in record.info.subscribers) {
/* do not send updates to request originator */
if(c.id == client.id)
continue;
var data = {
location:record.parent_name + "." + record.child_name,
data:record.data[record.child_name]
......@@ -617,9 +610,7 @@ Database = new (function() {
/* constructor */
this.init();
})();
}
};
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