cursors

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;
+}