From 6f5fc9616f566220a98fc4ad22a55be54104ef0e Mon Sep 17 00:00:00 2001
From: mcmlxxix <>
Date: Fri, 21 Oct 2011 18:18:32 +0000
Subject: [PATCH] non-existant record reads return undefined (and do not create
the record in the process), methods updated, initialize _locks and
_subscriptions as {} instead of [], a myriad of miscellaneous varieties of
other assorted sporadic changes.
---
exec/load/json-db.js | 226 +++++++++++++++++++++++++------------------
1 file changed, 132 insertions(+), 94 deletions(-)
diff --git a/exec/load/json-db.js b/exec/load/json-db.js
index a725aa9a73..7ba2144c2a 100644
--- a/exec/load/json-db.js
+++ b/exec/load/json-db.js
@@ -23,7 +23,7 @@
- Database.write(client,record,child_name,data);
- Database.push(client,record,child_name,data);
- Database.unshift(client,record,child_name,data);
- - Database.delete(client,record,child_name);
+ - Database.remove(client,record,child_name);
- Database.subscribe(client,record,child_name);
- Database.unsubscribe(client,record,child_name);
@@ -56,18 +56,9 @@ function JSONdb (fileName) {
/* database settings */
this.settings={
-
- /* record lock constants, incremental (do not change the order or value) */
- LOCK_UNLOCK:-1,
- LOCK_NONE:undefined,
- LOCK_READ:1,
- LOCK_WRITE:2,
-
- /* file read buffer */
- FILE_BUFFER:524288,
-
/* misc settings */
FILE:system.data_dir + "json-db.ini",
+ FILE_BUFFER:524288,
LAST_SAVE:-1,
SAVE_INTERVAL:-1,
KEEP_READABLE:false,
@@ -75,8 +66,16 @@ function JSONdb (fileName) {
UPDATES:false,
};
+ /* lock constants */
+ var locks = {
+ UNLOCK:-1,
+ NONE:undefined,
+ READ:1,
+ WRITE:2,
+ }
+
/* error constants */
- this.errors = {
+ var errors = {
INVALID_REQUEST:0,
OBJECT_NOT_FOUND:1,
NOT_LOCKED:2,
@@ -101,7 +100,7 @@ function JSONdb (fileName) {
send_subscriber_updates(client,record,"SUBSCRIBE");
}
else {
- this.error(client,this.errors.DUPLICATE_SUB);
+ this.error(client,errors.DUPLICATE_SUB);
}
return true;
};
@@ -116,7 +115,7 @@ function JSONdb (fileName) {
send_subscriber_updates(client,record,"UNSUBSCRIBE");
}
else {
- this.error(client,this.errors.INVALID_REQUEST);
+ this.error(client,errors.INVALID_REQUEST);
}
return true;
};
@@ -126,14 +125,14 @@ function JSONdb (fileName) {
this.lock = function(client,record,lock_type) {
switch(lock_type) {
/* if the client wants to read... */
- case this.settings.LOCK_READ:
+ case locks.READ:
/* if this is a duplicate lock attempt */
if(record.info.lock[client.id]) {
- this.error(client,this.errors.DUPLICATE_LOCK);
+ this.error(client,errors.DUPLICATE_LOCK);
return true;
}
switch(record.info.lock_type) {
- case this.settings.LOCK_READ:
+ case locks.READ:
/* if there are any pending write locks, deny */
if(record.info.lock_pending) {
return false;
@@ -147,10 +146,10 @@ function JSONdb (fileName) {
return true;
}
/* we cant lock a record that is already locked for reading */
- case this.settings.LOCK_WRITE:
+ case locks.WRITE:
return false;
/* if the record isnt locked at all, we can lock */
- case this.settings.LOCK_NONE:
+ case locks.NONE:
record.shadow[record.child_name]._lock[client.id] = new Lock(
lock_type,
Date.now()
@@ -159,25 +158,25 @@ function JSONdb (fileName) {
}
break;
/* if the client wants to write... */
- case this.settings.LOCK_WRITE:
+ case locks.WRITE:
/* if this db is read-only */
if(this.settings.READ_ONLY) {
- this.error(client,this.errors.READ_ONLY);
+ this.error(client,errors.READ_ONLY);
return true;
}
/* if this is a duplicate lock attempt */
if(record.info.lock[client.id]) {
- this.error(client,this.errors.DUPLICATE_LOCK);
+ this.error(client,errors.DUPLICATE_LOCK);
return true;
}
switch(record.info.lock_type) {
/* ...and the record is already locked, flag for pending write lock */
- case this.settings.LOCK_READ:
- case this.settings.LOCK_WRITE:
+ case locks.READ:
+ case locks.WRITE:
record.shadow[record.child_name]._lock_pending=true;
return false;
/* ...and the record isnt locked, lock for writing and remove flag */
- case this.settings.LOCK_NONE:
+ case locks.NONE:
record.shadow[record.child_name]._lock[client.id] = new Lock(
lock_type,
Date.now()
@@ -187,12 +186,12 @@ function JSONdb (fileName) {
}
break;
/* if the client wants to unlock, check credentials */
- case this.settings.LOCK_UNLOCK:
+ case locks.UNLOCK:
var client_lock=record.shadow[record.child_name]._lock[client.id];
/* if the client has a lock on this record, release the lock */
if(client_lock) {
/* if this was a write lock, send an update to all record subscribers */
- if(client_lock.type == this.settings.LOCK_WRITE) {
+ if(client_lock.type == locks.WRITE) {
this.settings.UPDATES=true;
send_data_updates(client,record);
}
@@ -201,7 +200,7 @@ function JSONdb (fileName) {
}
/* otherwise deny */
else {
- this.error(client,this.errors.NOT_LOCKED);
+ this.error(client,errors.NOT_LOCKED);
return true;
}
}
@@ -211,8 +210,13 @@ function JSONdb (fileName) {
/* server's data retrieval method (not directly called by client) */
this.read = function(client,record) {
+ /* if the requested data does not exist, result is undefined */
+ if(record.data === undefined) {
+ send_packet(client,undefined,"RESPONSE");
+ return true;
+ }
/* if this client has this record locked, read */
- if(record.info.lock[client.id]) {
+ else if(record.info.lock[client.id]) {
send_packet(client,record.data[record.child_name],"RESPONSE");
return true;
}
@@ -224,13 +228,18 @@ function JSONdb (fileName) {
/* pop a record off the end of an array */
this.pop = function(client,record) {
+ /* if the requested data does not exist, result is undefined */
+ if(record.data === undefined) {
+ send_packet(client,undefined,"RESPONSE");
+ return true;
+ }
/* if this client has this record locked */
- if(record.info.lock[client.id] &&
- record.info.lock[client.id].type == this.settings.LOCK_WRITE) {
+ else if(record.info.lock[client.id] &&
+ record.info.lock[client.id].type == locks.WRITE) {
if(typeof record.data[record.child_name].pop == "function")
send_packet(client,record.data[record.child_name].pop(),"RESPONSE");
else
- this.error(client,this.errors.NON_ARRAY);
+ this.error(client,errors.NON_ARRAY);
return true;
}
/* if there is no lock for this client, error */
@@ -241,13 +250,18 @@ function JSONdb (fileName) {
/* shift a record off the end of an array */
this.shift = function(client,record) {
+ /* if the requested data does not exist, result is undefined */
+ if(record.data === undefined) {
+ send_packet(client,undefined,"RESPONSE");
+ return true;
+ }
/* if this client has this record locked */
- if(record.info.lock[client.id] &&
- record.info.lock[client.id].type == this.settings.LOCK_WRITE) {
+ else if(record.info.lock[client.id] &&
+ record.info.lock[client.id].type == locks.WRITE) {
if(typeof record.data[record.child_name].shift == "function")
send_packet(client,record.data[record.child_name].shift(),"RESPONSE");
else
- this.error(client,this.errors.NON_ARRAY);
+ this.error(client,errors.NON_ARRAY);
return true;
}
/* if there is no lock for this client, error */
@@ -258,9 +272,14 @@ function JSONdb (fileName) {
/* push a record onto the end of an array */
this.push = function(client,record,data) {
+ /* if the requested data does not exist, result is undefined */
+ if(record.data === undefined) {
+ this.error(client,errors.OBJECT_NOT_FOUND);
+ return true;
+ }
/* if this client has this record locked */
- if(record.info.lock[client.id] &&
- record.info.lock[client.id].type == this.settings.LOCK_WRITE) {
+ else if(record.info.lock[client.id] &&
+ record.info.lock[client.id].type == locks.WRITE) {
if(typeof record.data[record.child_name].pop == "function") {
var index = record.data[record.child_name].length;
record.data[record.child_name].push(data);
@@ -268,7 +287,7 @@ function JSONdb (fileName) {
composite_sketch(record.data[record.child_name][index],record.shadow[record.child_name][index]);
}
else
- this.error(client,this.errors.NON_ARRAY);
+ this.error(client,errors.NON_ARRAY);
return true;
}
/* if there is no lock for this client, error */
@@ -279,9 +298,14 @@ function JSONdb (fileName) {
/* push a record onto the end of an array */
this.unshift = function(client,record,data) {
+ /* if the requested data does not exist, result is undefined */
+ if(record.data === undefined) {
+ this.error(client,errors.OBJECT_NOT_FOUND);
+ return true;
+ }
/* if this client has this record locked */
- if(record.info.lock[client.id] &&
- record.info.lock[client.id].type == this.settings.LOCK_WRITE) {
+ else if(record.info.lock[client.id] &&
+ record.info.lock[client.id].type == locks.WRITE) {
if(typeof record.data[record.child_name].unshift == "function") {
var index = record.data[record.child_name].length;
record.data[record.child_name].unshift(data);
@@ -289,7 +313,7 @@ function JSONdb (fileName) {
composite_sketch(record.data[record.child_name][index],record.shadow[record.child_name][index]);
}
else
- this.error(client,this.errors.NON_ARRAY);
+ this.error(client,errors.NON_ARRAY);
return true;
}
/* if there is no lock for this client, error */
@@ -303,7 +327,7 @@ function JSONdb (fileName) {
/* if this client has this record locked */
if(record.info.lock[client.id] &&
- record.info.lock[client.id].type == this.settings.LOCK_WRITE) {
+ record.info.lock[client.id].type == locks.WRITE) {
record.data[record.child_name]=data;
/* populate this object's children with shadow objects */
composite_sketch(record.data[record.child_name],record.shadow[record.child_name]);
@@ -317,10 +341,13 @@ function JSONdb (fileName) {
};
/* remove a record from the database (requires WRITE_LOCK) */
- this.delete = function(client,record) {
+ this.remove = function(client,record) {
+ /* if the requested data does not exist, do nothing */
+ if(record.data === undefined)
+ return true;
/* if this client has this record locked */
- if(record.shadow[record.child_name]._lock[client.id] &&
- record.shadow[record.child_name]._lock[client.id].type == this.settings.LOCK_WRITE) {
+ else if(record.shadow[record.child_name]._lock[client.id] &&
+ record.shadow[record.child_name]._lock[client.id].type == locks.WRITE) {
delete record.data[record.child_name];
delete record.shadow[record.child_name];
/* send data updates to all subscribers */
@@ -328,7 +355,7 @@ function JSONdb (fileName) {
}
/* if there is no lock for this client, error */
else {
- this.error(client,this.errors.NOT_LOCKED);
+ this.error(client,errors.NOT_LOCKED);
return false;
}
};
@@ -365,7 +392,7 @@ function JSONdb (fileName) {
/* if the data request is invalid or empty, return an error */
if(!child_name) {
- this.error(client,this.errors.INVALID_REQUEST);
+ this.error(client,errors.INVALID_REQUEST);
return false;
}
@@ -397,7 +424,7 @@ function JSONdb (fileName) {
));
/* put unlock after the operation in the request queue */
q.push(new Request(
- client,"LOCK",parent_name,child_name,this.settings.LOCK_UNLOCK
+ client,"LOCK",parent_name,child_name,locks.UNLOCK
));
}
@@ -409,28 +436,28 @@ function JSONdb (fileName) {
this.error = function(client,error_num) {
var error_desc="Unknown error";
switch(error_num) {
- case this.errors.INVALID_REQUEST:
+ case errors.INVALID_REQUEST:
error_desc="Invalid record request";
break;
- case this.errors.OBJECT_NOT_FOUND:
+ case errors.OBJECT_NOT_FOUND:
error_desc="Record not found";
break;
- case this.errors.NOT_LOCKED:
+ case errors.NOT_LOCKED:
error_desc="Record not locked";
break;
- case this.errors.LOCKED_WRITE:
+ case errors.LOCKED_WRITE:
error_desc="Record locked for writing";
break;
- case this.errors.LOCKED_READ:
+ case errors.LOCKED_READ:
error_desc="Record locked for reading";
break;
- case this.errors.DUPLICATE_LOCK:
+ case errors.DUPLICATE_LOCK:
error_desc="Duplicate record lock request";
break;
- case this.errors.DUPLICATE_SUBSCRIPTION:
+ case errors.DUPLICATE_SUBSCRIPTION:
error_desc="Duplicate record subscription request";
break;
- case this.errors.NON_ARRAY:
+ case errors.NON_ARRAY:
error_desc="Record is not an array";
break;
case this.settings.READ_ONLY:
@@ -516,10 +543,10 @@ function JSONdb (fileName) {
for(var r=0;r<this.queue.length;r++) {
var request=this.queue[r];
var result=false;
-
/* locate the requested record within the database */
var record=identify_remains.call(
- this,request.client,request.parent_name,request.child_name
+ this,request.client,request.parent_name,request.child_name,
+ request.oper.toUpperCase() == "WRITE"
);
if(!record) {
@@ -548,7 +575,7 @@ function JSONdb (fileName) {
result=this.unshift(request.client,record,request.data);
break;
case "DELETE":
- result=this.delete(request.client,record);
+ result=this.remove(request.client,record);
break;
case "CREATE":
result=this.create(request.client,record,request.data);
@@ -612,9 +639,9 @@ function JSONdb (fileName) {
/* shadow properties generated by composite_sketch()
contains a relative object's subscribers, locks, and child name */
function Shadow() {
- this._lock=[];
+ this._lock={};
this._lock_pending=false;
- this._subscribers=[];
+ this._subscribers={};
}
/* record object returned by identify_remains()
@@ -663,57 +690,61 @@ function JSONdb (fileName) {
/* parse an object location name and return the object (ex: dicewarz2.games.1.players.1.tiles.0)
an object containing the corresponding data and its shadow object */
- function identify_remains(client,parent_name,child_name) {
+ function identify_remains(client,parent_name,child_name,create_new) {
var data=this.data;
var shadow=this.shadow;
var location=child_name;
var info={
- lock:[],
- lock_type:this.settings.LOCK_NONE,
+ lock:{},
+ lock_type:locks.NONE,
lock_pending:false,
- subscribers:[]
- }
+ subscribers:{}
+ };
if(parent_name !== undefined) {
/* iterate through split object name checking the keys against the database and
checking the lock statuses against the shadow copy */
var p=parent_name.split(/\./);
for each(var c in p) {
-
- verify(data,shadow,c);
-
+ /* in the event of a write request, create new data if it does not exist*/
+ if(data[c] === undefined && create_new)
+ create_data(data,c);
+ /* ensure that the shadow object exists in order to allow for non-read operations */
+ if(shadow[c] === undefined)
+ create_shadow(data,c);
/* keep track of current object, and store the immediate parent of the request object */
- data=data[c];
+ if(data !== undefined)
+ data=data[c];
shadow=shadow[c];
-
/* check the current object's lock and subscriber status along the way */
info = investigate(shadow,info);
}
location = parent_name + "." + child_name;
}
- /* ensure requested object's existance */
- verify(data,shadow,child_name);
+ /* ensure requested shadow object's existance */
+ if(shadow[child_name] === undefined)
+ create_shadow(shadow,child_name);
/* continue on through the selected shadow object's children to check for locked children */
- info = search_party(data[child_name],shadow[child_name],info);
+ info = search_party(shadow[child_name],info);
/* return selected database object, shadow object, and overall lock status of the chosen tree */
return new Record(data,shadow,location,child_name,info);
}
/* if the requested child object does not exist, create it */
- function verify(data,shadow,child_name) {
- if(data[child_name] === undefined) {
- log(LOG_DEBUG,"creating new data: " + child_name);
- data[child_name]={};
- }
- if(shadow[child_name] === undefined) {
- log(LOG_DEBUG,"creating new shadow: " + child_name);
- shadow[child_name]=new Shadow();
- }
- }
+ function create_shadow(shadow,child_name) {
+ log(LOG_DEBUG,"creating new shadow: " + child_name);
+ shadow[child_name]=new Shadow();
+ }
+
+ /* if the requested child object does not exist, create it */
+ function create_data(data,child_name) {
+ log(LOG_DEBUG,"creating new data: " + child_name);
+ data[child_name]={};
+ }
/* release locks on an object recursively */
function free_prisoners(client,shadow) {
@@ -731,8 +762,8 @@ function JSONdb (fileName) {
function cancel_subscriptions(client,records) {
for(var r in records) {
var record = records[r];
- log(LOG_DEBUG,"releasing subscription: " + client.id);
- delete record.shadow._subscribers[client.id];
+ log(LOG_DEBUG,"releasing subscription: " + record.location);
+ delete record.shadow[record.child_name]._subscribers[client.id];
send_subscriber_updates(client,record,"UNSUBSCRIBE");
}
}
@@ -754,15 +785,14 @@ function JSONdb (fileName) {
}
/* recursively search object for any existing locked children,
- return highest lock level (LOCK_WRITE > LOCK_READ > LOCK_NONE) */
- function search_party(data,shadow,info) {
- if(!shadow)
+ return highest lock level (WRITE > READ > NONE) */
+ function search_party(shadow,info) {
+ if(shadow == undefined)
return info;
-
info = investigate(shadow,info);
- for(var i in data) {
- info = search_party(data[i],shadow[i],info);
- }
+ for each(var i in shadow)
+ if(i instanceof Shadow)
+ info = search_party(i,info);
return info;
}
@@ -774,12 +804,19 @@ function JSONdb (fileName) {
continue;
var data = {
location:record.location,
- data:record.data[record.child_name]
+ data:get_record_data(record)
};
send_packet(c,data,"UPDATE");
}
}
+ /* retrieve record data, if present */
+ function get_record_data(record) {
+ if(record.data === undefined)
+ return undefined;
+ return record.data[record.child_name];
+ }
+
/* send update of client subscription to all subscribers */
function send_subscriber_updates(client,record,oper) {
var data = {
@@ -795,6 +832,7 @@ function JSONdb (fileName) {
}
}
+ /* retrieve client nickname and system name, if present, from client socket */
function get_client_info(client) {
return {
id:client.id,
--
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