cursors

db/db.cpp

@@ -56,6 +56,13 @@ public:
 		nextjsobj += 4;
 		return i;
 	}
+	long long pullInt64() {
+		if( nextjsobj == data )
+			nextjsobj += strlen(data) + 1; // skip namespace
+		long long i = *((long long *)nextjsobj);
+		nextjsobj += 8;
+		return i;
+	}
 
 	OID* getOID() {
 		return (OID *) (data + strlen(data) + 1); // skip namespace
@@ -135,7 +142,6 @@ void receivedDelete(Message& m) {
 
 void receivedQuery(Message& m) {
 	DbMessage d(m);
-
 	const char *ns = d.getns();
 	int ntoreturn = d.pullInt();
 	assert( d.moreJSObjs() );
@@ -145,6 +151,17 @@ void receivedQuery(Message& m) {
 	dbMsgPort.reply(m, resp);
 }
 
+void receivedGetMore(Message& m) {
+	DbMessage d(m);
+	const char *ns = d.getns();
+	int ntoreturn = d.pullInt();
+	long long cursorid = d.pullInt64();
+	QueryResult* msgdata = getMore(ns, ntoreturn, cursorid);
+	Message resp;
+	resp.setData(msgdata, true);
+	dbMsgPort.reply(m, resp);
+}
+
 /*void getbyoid(Message& m) {
 	DbMessage d(m);
 	Record *r = findByOID(d.getns(), d.getOID());

db/jsobj.cpp

@@ -91,19 +91,16 @@ JSMatcher::JSMatcher(JSObj &_jsobj) :
 
 struct RXTest { 
 	RXTest() { 
-//		pcre_compile(0, 0, 0, 0, 0);
-//pcre_compile(const char *, int, const char **, int *,
-//			 const unsigned char *);
-
-/*
+		/*
 		static const boost::regex e("(\\d{4}[- ]){3}\\d{4}");
 		static const boost::regex b(".....");
 		cout << "regex result: " << regex_match("hello", e) << endl;
 		cout << "regex result: " << regex_match("abcoo", b) << endl;
-*/
-		pcrecpp::RE re("h.*o");
-		cout << "regex test: " << re.FullMatch("hello") << endl;
-		cout << "regex test: " << re.FullMatch("blah") << endl;
+		*/
+		pcrecpp::RE re1(")({a}h.*o");
+		pcrecpp::RE re("h.llo");
+		assert( re.FullMatch("hello") );
+		assert( !re1.FullMatch("hello") );
 	}
 } rxtest;
 

db/query.cpp

@@ -5,6 +5,7 @@
 #include "pdfile.h"
 #include "jsobj.h"
 #include "../util/builder.h"
+#include <time.h>
 
 int nextCursorId = 1;
 
@@ -65,13 +66,28 @@ void updateObjects(const char *ns, JSObj updateobj, JSObj pattern, bool upsert)
 		theDataFileMgr.insert(ns, (void*) updateobj.objdata(), updateobj.objsize());
 }
 
+typedef map<long long, ClientCursor*> CCMap;
+CCMap clientCursors;
+
+long long allocCursorId() { 
+	long long x;
+	while( 1 ) {
+		x = (((long long)rand()) << 32);
+		x = x | time(0);
+		if( clientCursors.count(x) == 0 )
+			break;
+	}
+	return x;
+}
+
 QueryResult* runQuery(const char *ns, int ntoreturn, JSObj jsobj) {
 
 	cout << "runQuery ns:" << ns << " ntoreturn:" << ntoreturn << " queryobjsize:" << 
 		jsobj.objsize() << endl;
 
 	BufBuilder b;
-	JSMatcher matcher(jsobj);
+
+	auto_ptr<JSMatcher> matcher(new JSMatcher(jsobj));
 
 	QueryResult *qr = 0;
 	b.skip(sizeof(QueryResult));
@@ -79,17 +95,28 @@ QueryResult* runQuery(const char *ns, int ntoreturn, JSObj jsobj) {
 	int n = 0;
 
 	auto_ptr<Cursor> c = 
-//		strcmp(ns, "system.namespaces") == 0 ? 
-//		makeNamespaceCursor() : 
+		//		strcmp(ns, "system.namespaces") == 0 ? 
+		//		makeNamespaceCursor() : 
 	    theDataFileMgr.findAll(ns);
 
+	long long cursorid = 0;
 	while( c->ok() ) {
 		JSObj js = c->current();
-		if( matcher.matches(js) ) {
+		if( matcher->matches(js) ) {
 			b.append((void*) js.objdata(), js.objsize());
 			n++;
-			if( n >= ntoreturn && ntoreturn != 0 )
+			if( n >= ntoreturn && ntoreturn != 0 ) {
+				// more...so save a cursor
+				ClientCursor *cc = new ClientCursor();
+				cc->c = c;
+				cursorid = allocCursorId();
+				cc->cursorid = cursorid;
+				cc->matcher = matcher;
+				cc->ns = ns;
+				cc->pos = n;
+				clientCursors[cursorid] = cc;
 				break;
+			}
 		}
 		c->advance();
 	}
@@ -98,10 +125,68 @@ QueryResult* runQuery(const char *ns, int ntoreturn, JSObj jsobj) {
 	qr->len = b.len();
 	qr->reserved = 0;
 	qr->operation = opReply;
-	qr->cursorId = 0; //nextCursorId++;
+	qr->cursorId = cursorid;
 	qr->startingFrom = 0;
 	qr->nReturned = n;
 	b.decouple();
 
 	return qr;
 }
+
+QueryResult* getMore(const char *ns, int ntoreturn, long long cursorid) {
+
+	cout << "getMore ns:" << ns << " ntoreturn:" << ntoreturn << " cursorid:" << 
+		cursorid << endl;
+
+	BufBuilder b;
+
+	ClientCursor *cc = 0;
+	CCMap::iterator it = clientCursors.find(cursorid);
+	if( it == clientCursors.end() ) { 
+		cout << "Cursor not found in map.  cursorid: " << cursorid << endl;
+	}
+	else {
+		cc = it->second;
+	}
+
+	b.skip(sizeof(QueryResult));
+
+	int start = 0;
+	int n = 0;
+
+	if( cc ) {
+		start = cc->pos;
+		Cursor *c = cc->c.get();
+		while( 1 ) {
+			if( !c->ok() ) {
+				// done!  kill cursor.
+				cursorid = 0;
+				clientCursors.erase(it);
+				delete cc;
+				cc = 0;
+				break;
+			}
+			JSObj js = c->current();
+			if( cc->matcher->matches(js) ) {
+				b.append((void*) js.objdata(), js.objsize());
+				n++;
+				if( n >= ntoreturn && ntoreturn != 0 ) {
+					cc->pos += n;
+					break;
+				}
+			}
+		}
+		c->advance();
+	}
+
+	QueryResult *qr = (QueryResult *) b.buf();
+	qr->cursorId = cursorid;
+	qr->startingFrom = start;
+	qr->len = b.len();
+	qr->reserved = 0;
+	qr->operation = opReply;
+	qr->nReturned = n;
+	b.decouple();
+
+	return qr;
+}

db/query.h

@@ -25,9 +25,10 @@
 	  int nToReturn; // how many you want back as the beginning of the cursor data
       JSObject query;
    dbGetMore:
-      int reserved;;
-      int64 cursorID;
+      int reserved;
+	  string collection; // redundant, might use for security.
       int nToReturn;
+      int64 cursorID;
 
    Note that on Update, there is only one object, which is different
    from insert where you can pass a list of objects to insert in the db.
@@ -51,7 +52,20 @@ struct QueryResult : public MsgData {
 	const char *data() { return (char *) (((int *)&nReturned)+1); }
 };
 
+QueryResult* getMore(const char *ns, int ntoreturn, long long cursorid);
 QueryResult* runQuery(const char *ns, int ntoreturn, JSObj);
 
 void updateObjects(const char *ns, JSObj updateobj, JSObj pattern, bool upsert);
 void deleteObjects(const char *ns, JSObj pattern, bool justOne);
+
+class Cursor;
+class ClientCursor {
+public:
+	ClientCursor() { cursorid=0; pos=0; }
+	long long cursorid;
+	string ns;
+	auto_ptr<JSMatcher> matcher;
+	auto_ptr<Cursor> c;
+	int pos;
+};
+