Merge branch 'master' of git@github.com:mongodb/mongo

2 files changed, 97 insertions, 86 deletions

diff --git a/db/namespace.cpp b/db/namespace.cpp
index a5c21439876..b34e379f7b7 100644
--- a/db/namespace.cpp
+++ b/db/namespace.cpp
@@ -1,4 +1,4 @@
-// namespacedetails.cpp
+// namespace.cpp
 
 /**
 *    Copyright (C) 2008 10gen Inc.
@@ -32,7 +32,7 @@ namespace mongo {
 
     BSONObj idKeyPattern = fromjson("{\"_id\":1}");
 
-    /* deleted lists -- linked lists of deleted records -- tehy are placed in 'buckets' of various sizes
+    /* deleted lists -- linked lists of deleted records -- are placed in 'buckets' of various sizes
        so you can look for a deleterecord about the right size.
     */
     int bucketSizes[] = {
@@ -41,8 +41,6 @@ namespace mongo {
         0x400000, 0x800000
     };
 
-//NamespaceIndexMgr namespaceIndexMgr;
-
     bool NamespaceIndex::exists() const {
         return !boost::filesystem::exists(path());        
     }
@@ -222,9 +220,7 @@ namespace mongo {
     }
 
     void NamespaceDetails::dumpDeleted(set<DiskLoc> *extents) {
-//	out() << "DUMP deleted chains" << endl;
         for ( int i = 0; i < Buckets; i++ ) {
-//		out() << "  bucket " << i << endl;
             DiskLoc dl = deletedList[i];
             while ( !dl.isNull() ) {
                 DeletedRecord *r = dl.drec();
@@ -239,7 +235,6 @@ namespace mongo {
                 dl = r->nextDeleted;
             }
         }
-//	out() << endl;
     }
 
     /* combine adjacent deleted records
@@ -548,9 +543,9 @@ namespace mongo {
         allIndexKeys.clear();
         NamespaceDetails *d = nsdetails(ns.c_str());
         for ( int i = 0; i < d->nIndexes; i++ ) {
-//        set<string> fields;
+			// set<string> fields;
             d->indexes[i].keyPattern().getFieldNames(allIndexKeys);
-//        allIndexKeys.insert(fields.begin(),fields.end());
+			// allIndexKeys.insert(fields.begin(),fields.end());
         }
     }
     
@@ -614,67 +609,68 @@ namespace mongo {
         }
     }
 
-  void renameNamespace( const char *from, const char *to ) {
-    NamespaceIndex *ni = nsindex( from );
-    assert( ni && ni->details( from ) && !ni->details( to ) );
-
-    // Our namespace and index details will move to a different 
-    // memory location.  The only references to namespace and 
-    // index details across commands are in cursors and nsd
-    // transient (including query cache) so clear these.
-    ClientCursor::invalidate( from );
-    NamespaceDetailsTransient::drop( from );
-
-    NamespaceDetails *details = ni->details( from );
-    ni->add( to, *details );
-    ni->drop( from );
-    details = ni->details( to );
-
-    BSONObj oldSpec;
-    char database[256];
-    nsToClient(from, database);
-    string s = database;
-    s += ".system.namespaces";
-    assert( Helpers::findOne( s.c_str(), BSON( "name" << from ), oldSpec ) );
-
-    BSONObjBuilder newSpecB;
-    BSONObjIterator i( oldSpec.getObjectField( "options" ) );
-    while( i.more() ) {
-      BSONElement e = i.next();
-      if ( strcmp( e.fieldName(), "create" ) != 0 )
-	newSpecB.append( e );
-      else
-	newSpecB << "create" << to;
-    }
-    BSONObj newSpec = newSpecB.done();    
-    addNewNamespaceToCatalog( to, newSpec.isEmpty() ? 0 : &newSpec );
-
-    deleteObjects( s.c_str(), BSON( "name" << from ), false, false, true );
-    // oldSpec variable no longer valid memory
-
-    BSONObj oldIndexSpec;
-    s = database;
-    s += ".system.indexes";
-    while( Helpers::findOne( s.c_str(), BSON( "ns" << from ), oldIndexSpec ) ) {
-      BSONObjBuilder newIndexSpecB;
-      BSONObjIterator i( oldIndexSpec );
-      while( i.more() ) {
-	BSONElement e = i.next();
-	if ( strcmp( e.fieldName(), "ns" ) != 0 )
-	  newIndexSpecB.append( e );
-	else
-	  newIndexSpecB << "ns" << to;
-      }
-      BSONObj newIndexSpec = newIndexSpecB.done();
-      DiskLoc newIndexSpecLoc = theDataFileMgr.insert( s.c_str(), newIndexSpec.objdata(), newIndexSpec.objsize(), true, BSONElement(), false );
-      int indexI = details->findIndexByName( oldIndexSpec.getStringField( "name" ) );
-      IndexDetails &indexDetails = details->indexes[ indexI ];
-      string oldIndexNs = indexDetails.indexNamespace();
-      indexDetails.info = newIndexSpecLoc;
-      string newIndexNs = indexDetails.indexNamespace();
-
-      BtreeBucket::renameIndexNamespace( oldIndexNs.c_str(), newIndexNs.c_str() );
-      deleteObjects( s.c_str(), oldIndexSpec.getOwned(), true, false, true );
-    }
-  }
+    void renameNamespace( const char *from, const char *to ) {
+		NamespaceIndex *ni = nsindex( from );
+		assert( ni && ni->details( from ) && !ni->details( to ) );
+		
+		// Our namespace and index details will move to a different 
+		// memory location.  The only references to namespace and 
+		// index details across commands are in cursors and nsd
+		// transient (including query cache) so clear these.
+		ClientCursor::invalidate( from );
+		NamespaceDetailsTransient::drop( from );
+		
+		NamespaceDetails *details = ni->details( from );
+		ni->add( to, *details );
+		ni->drop( from );
+		details = ni->details( to );
+		
+		BSONObj oldSpec;
+		char database[MaxClientLen];
+		nsToClient(from, database);
+		string s = database;
+		s += ".system.namespaces";
+		assert( Helpers::findOne( s.c_str(), BSON( "name" << from ), oldSpec ) );
+		
+		BSONObjBuilder newSpecB;
+		BSONObjIterator i( oldSpec.getObjectField( "options" ) );
+		while( i.more() ) {
+			BSONElement e = i.next();
+			if ( strcmp( e.fieldName(), "create" ) != 0 )
+				newSpecB.append( e );
+			else
+				newSpecB << "create" << to;
+		}
+		BSONObj newSpec = newSpecB.done();    
+		addNewNamespaceToCatalog( to, newSpec.isEmpty() ? 0 : &newSpec );
+
+		deleteObjects( s.c_str(), BSON( "name" << from ), false, false, true );
+		// oldSpec variable no longer valid memory
+
+		BSONObj oldIndexSpec;
+		s = database;
+		s += ".system.indexes";
+		while( Helpers::findOne( s.c_str(), BSON( "ns" << from ), oldIndexSpec ) ) {
+			BSONObjBuilder newIndexSpecB;
+			BSONObjIterator i( oldIndexSpec );
+			while( i.more() ) {
+				BSONElement e = i.next();
+				if ( strcmp( e.fieldName(), "ns" ) != 0 )
+					newIndexSpecB.append( e );
+				else
+					newIndexSpecB << "ns" << to;
+			}
+			BSONObj newIndexSpec = newIndexSpecB.done();
+			DiskLoc newIndexSpecLoc = theDataFileMgr.insert( s.c_str(), newIndexSpec.objdata(), newIndexSpec.objsize(), true, BSONElement(), false );
+			int indexI = details->findIndexByName( oldIndexSpec.getStringField( "name" ) );
+			IndexDetails &indexDetails = details->indexes[ indexI ];
+			string oldIndexNs = indexDetails.indexNamespace();
+			indexDetails.info = newIndexSpecLoc;
+			string newIndexNs = indexDetails.indexNamespace();
+			
+			BtreeBucket::renameIndexNamespace( oldIndexNs.c_str(), newIndexNs.c_str() );
+			deleteObjects( s.c_str(), oldIndexSpec.getOwned(), true, false, true );
+		}
+	}
+	
 } // namespace mongo
diff --git a/db/namespace.h b/db/namespace.h
index 4a207f4a557..4470aa63f09 100644
--- a/db/namespace.h
+++ b/db/namespace.h
@@ -19,11 +19,9 @@
 #pragma once
 
 #include "../stdafx.h"
-
 #include "jsobj.h"
 #include "queryutil.h"
 #include "storage.h"
-
 #include "../util/hashtab.h"
 #include "../util/mmap.h"
 
@@ -33,8 +31,11 @@ namespace mongo {
 
 #pragma pack(1)
 
-// "database.a.b.c" -> "database"
-    const int MaxClientLen = 256;
+	/* in the mongo source code, "client" means "database". */
+
+    const int MaxClientLen = 256; // max str len for the db name
+
+	// "database.a.b.c" -> "database"
     inline void nsToClient(const char *ns, char *database) {
         const char *p = ns;
         char *q = database;
@@ -55,10 +56,14 @@ namespace mongo {
         return buf;
     }
 
+	/* e.g.
+	   NamespaceString ns("acme.orders");
+	   cout << ns.coll; // "orders"
+	*/
     class NamespaceString {
     public:
         string db;
-        string coll;
+        string coll; // note collection names can have periods in them for organizing purposes (e.g. "system.indexes")
     private:
         void init(const char *ns) { 
             const char *p = strchr(ns, '.');
@@ -71,6 +76,7 @@ namespace mongo {
         NamespaceString( const string& ns ) { init(ns.c_str()); }
     };
 
+	/* This helper class is used to make the HashMap below in NamespaceDetails */
     class Namespace {
     public:
         enum MaxNsLenValue { MaxNsLen = 128 };
@@ -106,6 +112,7 @@ namespace mongo {
 
         /**
            ( foo.bar ).getSisterNS( "blah" ) == foo.blah
+		   perhaps this should move to the NamespaceString helper?
          */
         string getSisterNS( const char * local ) {
             assert( local && local[0] != '.' );
@@ -118,23 +125,31 @@ namespace mongo {
         char buf[MaxNsLen];
     };
 
+    /* deleted lists -- linked lists of deleted records -- are placed in 'buckets' of various sizes
+       so you can look for a deleterecord about the right size.
+    */
     const int Buckets = 19;
     const int MaxBucket = 18;
-    const int MaxIndexes = 10;
 
-    //extern BSONObj idKeyPattern; // { _id : 1 } 
+	/* Maximum # of indexes per collection.  We need to raise this limit at some point.  
+	   (Backward datafile compatibility is main issue with changing.)
+	*/
+    const int MaxIndexes = 10;
 
+	/* Details about a particular index. There is one of these effectively for each object in 
+	   system.namespaces (although this also includes the head pointer, which is not in that 
+	   collection).
+	 */
     class IndexDetails {
     public:
-        DiskLoc head; /* btree head */
+        DiskLoc head; /* btree head disk location */
 
         /* Location of index info object. Format:
 
              { name:"nameofindex", ns:"parentnsname", key: {keypattobject}[, unique: <bool>] }
 
            This object is in the system.indexes collection.  Note that since we
-           have a pointer to the object here, the object in system.indexes must
-           never move.
+           have a pointer to the object here, the object in system.indexes MUST NEVER MOVE.
         */
         DiskLoc info;
 
@@ -491,14 +506,14 @@ namespace mongo {
 
         void add(const char *ns, DiskLoc& loc, bool capped) {
             NamespaceDetails details( loc, capped );
-	    add( ns, details );
+			add( ns, details );
         }
 
-	void add( const char *ns, const NamespaceDetails &details ) {
+		void add( const char *ns, const NamespaceDetails &details ) {
             init();
             Namespace n(ns);
             uassert("too many namespaces/collections", ht->put(n, details));
-	}
+		}
 
         /* just for diagnostics */
         size_t detailsOffset(NamespaceDetails *d) {
@@ -553,7 +568,7 @@ namespace mongo {
         string database_;
     };
 
-    extern string dbpath;
+    extern string dbpath; // --dbpath parm 
 
     // Rename a namespace within current 'client' db.
     // (Arguments should include db name)