clean balancer policy a bit in prep of SERVER-2545

1 files changed, 59 insertions, 43 deletions

diff --git a/src/mongo/s/balancer_policy.h b/src/mongo/s/balancer_policy.h
index cef5aa64afc..ffc4853f3d9 100644
--- a/src/mongo/s/balancer_policy.h
+++ b/src/mongo/s/balancer_policy.h
@@ -19,78 +19,94 @@
 #ifndef S_BALANCER_POLICY_HEADER
 #define S_BALANCER_POLICY_HEADER
 
-#include "../pch.h"
+#include "mongo/db/jsobj.h"
 
 namespace mongo {
 
     class BalancerPolicy {
     public:
-        struct ChunkInfo;
-
+        struct MigrateInfo;
+
+        struct ChunkInfo {
+            const BSONObj min;
+            const BSONObj max;
+            
+            ChunkInfo( const BSONObj& a_min, const BSONObj& a_max ) 
+                : min( a_min ), max( a_max ){}
+
+            ChunkInfo( const BSONObj& chunk ) 
+                : min( chunk["min"].Obj() ), max( chunk["max"].Obj() ) {
+            }
+
+            string toString() const;
+        };
+
+        class ShardInfo {
+        public:
+            ShardInfo();
+            ShardInfo( long long maxSize, long long currSize, bool draining, bool opsQueued );
+            
+            /**
+             * @return true if a shard cannot receive any new chunks bacause it reache 'shardLimits'.
+             * Expects the optional fields "maxSize", can in size in MB, and "usedSize", currently used size
+             * in MB, on 'shardLimits'.
+             */
+            bool isSizeMaxed() const;
+
+            /**
+             * @return true if 'shardLimist' contains a field "draining". Expects the optional field
+             * "isDraining" on 'shrdLimits'.
+             */
+            bool isDraining() const { return _draining; }
+
+            /**
+             * @return true if a shard currently has operations in any of its writeback queues
+             */
+            bool hasOpsQueued() const { return _hasOpsQueued; }
+
+            string toString() const;
+
+        private:
+            long long _maxSize;
+            long long _currSize;
+            bool _draining;
+            bool _hasOpsQueued;
+        };
+        
         /**
          * Returns a suggested chunk to move whithin a collection's shards, given information about
          * space usage and number of chunks for that collection. If the policy doesn't recommend
          * moving, it returns NULL.
          *
          * @param ns is the collections namepace.
-         * @param shardLimitMap is a map from shardId to an object that describes (for now) space
-         * cap and usage. E.g.: { "maxSize" : <size_in_MB> , "usedSize" : <size_in_MB> }.
          * @param shardToChunksMap is a map from shardId to chunks that live there. A chunk's format
          * is { }.
          * @param balancedLastTime is the number of chunks effectively moved in the last round.
-         * @returns NULL or ChunkInfo of the best move to make towards balacing the collection.
+         * @returns NULL or MigrateInfo of the best move to make towards balacing the collection.
          */
-        typedef map< string,BSONObj > ShardToLimitsMap;
+        typedef map< string,ShardInfo > ShardInfoMap;
         typedef map< string,vector<BSONObj> > ShardToChunksMap;
-        static ChunkInfo* balance( const string& ns, const ShardToLimitsMap& shardToLimitsMap,
-                                   const ShardToChunksMap& shardToChunksMap, int balancedLastTime );
+        static MigrateInfo* balance( const string& ns, 
+                                   const ShardInfoMap& shardInfo,
+                                   const ShardToChunksMap& shardToChunksMap, 
+                                   int balancedLastTime );
 
         // below exposed for testing purposes only -- treat it as private --
 
         static BSONObj pickChunk( const vector<BSONObj>& from, const vector<BSONObj>& to );
 
-        /**
-         * Returns true if a shard cannot receive any new chunks bacause it reache 'shardLimits'.
-         * Expects the optional fields "maxSize", can in size in MB, and "usedSize", currently used size
-         * in MB, on 'shardLimits'.
-         */
-        static bool isSizeMaxed( BSONObj shardLimits );
-
-        /**
-         * Returns true if 'shardLimist' contains a field "draining". Expects the optional field
-         * "isDraining" on 'shrdLimits'.
-         */
-        static bool isDraining( BSONObj shardLimits );
-
-        /**
-         * Returns true if a shard currently has operations in any of its writeback queues
-         */
-        static bool hasOpsQueued( BSONObj shardLimits );
-
-    private:
-        // Convenience types
-        typedef ShardToChunksMap::const_iterator ShardToChunksIter;
-        typedef ShardToLimitsMap::const_iterator ShardToLimitsIter;
-
     };
 
-    struct BalancerPolicy::ChunkInfo {
+    struct BalancerPolicy::MigrateInfo {
         const string ns;
         const string to;
         const string from;
-        const BSONObj chunk;
+        const ChunkInfo chunk;
 
-        ChunkInfo( const string& a_ns , const string& a_to , const string& a_from , const BSONObj& a_chunk )
+        MigrateInfo( const string& a_ns , const string& a_to , const string& a_from , const BSONObj& a_chunk )
             : ns( a_ns ) , to( a_to ) , from( a_from ), chunk( a_chunk ) {}
-    };
 
-    /**
-     * Field names used in the 'limits' map.
-     */
-    struct LimitsFields {
-        // we use 'draining' and 'maxSize' from the 'shards' collection plus the following
-        static BSONField<long long> currSize; // currently used disk space in bytes
-        static BSONField<bool> hasOpsQueued;  // writeback queue is not empty?
+
     };
 
 }  // namespace mongo