Change storage engine getter to return via delegate

This improves performance by reducing by one the number of times the value(s) gets copied before being returned. The requests affected in this change are Get, GetChannelSize, GetChannels, GetNumConnections, GetResponsibleRange, GetSize. Fixes #144
sociomantic-tsunami · May 27, 2019 · 67e6c2b · 67e6c2b
1 parent 82f4dfd
commit 67e6c2b
Show file tree

Hide file tree

Showing 13 changed files with 130 additions and 79 deletions.
diff --git a/relnotes/GetterRequests.migration.md b/relnotes/GetterRequests.migration.md
@@ -0,0 +1,11 @@
+### Request getters return values via delegates
+
+`dhtproto.node.request.Get`, `dhtproto.node.request.GetChannelSize`,
+`dhtproto.node.request.GetChannels`, `dhtproto.node.request.GetNumConnections`,
+`dhtproto.node.request.GetResponsibleRange`, `dhtproto.node.request.GetSize`,
+`fakedht.request.Get`, `fakedht.request.GetChannelSize`,
+`fakedht.request.GetChannels`, `fakedht.request.GetNumConnections`,
+`fakedht.request.GetResponsibleRange`, `fakedht.request.GetSize`
+
+This improves performance by reducing by one the number of times the
+value(s) gets copied before being returned.
diff --git a/src/dhtproto/node/request/Get.d b/src/dhtproto/node/request/Get.d
@@ -91,7 +91,12 @@ public abstract scope class Get : SingleKey
         cstring key )
     {
         this.writer.write(DhtConst.Status.E.Ok);
-        this.writer.writeArray(this.getValue(channel_name, key));
+        this.getValue(channel_name, key,
+            ( const(void)[] value )
+            {
+                this.writer.writeArray(value);
+            }
+        );
     }
 
     /***************************************************************************
@@ -102,11 +107,13 @@ public abstract scope class Get : SingleKey
         Params:
             channel_name = name of channel to query
             key = key of record to find
+            value_getter_dg = The delegate that is called with the value.
 
         Returns:
             value of queried record, empty array if not found
 
     ***************************************************************************/
 
-    abstract protected Const!(void)[] getValue ( cstring channel_name, cstring key );
+    abstract protected void getValue ( cstring channel_name, cstring key,
+        scope void delegate ( const(void)[] ) value_getter_dg );
 }
diff --git a/src/dhtproto/node/request/GetChannelSize.d b/src/dhtproto/node/request/GetChannelSize.d
@@ -78,13 +78,16 @@ public abstract scope class GetChannelSize : SingleChannel
     {
         this.writer.write(DhtConst.Status.E.Ok);
 
-        auto data = this.getChannelData(channel_name);
-
-        // TODO: is there a need to send the addr/port? surely the client knows this anyway?
-        this.writer.writeArray(data.address);
-        this.writer.write(data.port);
-        this.writer.write(data.records);
-        this.writer.write(data.bytes);
+        this.getChannelData(channel_name,
+            ( ChannelSizeData data )
+            {
+                // TODO: is there a need to send the addr/port?
+                // surely the client knows this anyway?
+                this.writer.writeArray(data.address);
+                this.writer.write(data.port);
+                this.writer.write(data.records);
+                this.writer.write(data.bytes);
+            });
     }
 
     /***************************************************************************
@@ -94,8 +97,10 @@ public abstract scope class GetChannelSize : SingleChannel
 
         Params:
             channel_name = name of channel to be queried
+            value_getter_dg = The delegate that is called with the channel data.
 
     ***************************************************************************/
 
-    abstract protected ChannelSizeData getChannelData ( cstring channel_name );
+    abstract protected void getChannelData ( cstring channel_name,
+        scope void delegate ( ChannelSizeData ) value_getter_dg );
 }
diff --git a/src/dhtproto/node/request/GetChannels.d b/src/dhtproto/node/request/GetChannels.d
@@ -66,21 +66,24 @@ public abstract scope class GetChannels : DhtCommand
     final override protected void handleRequest ( )
     {
         this.writer.write(DhtConst.Status.E.Ok);
-        foreach (id; this.getChannelsIds())
-        {
-            this.writer.writeArray(id);
-        }
+        this.getChannelsIds(
+            ( const(void)[] id )
+            {
+                this.writer.writeArray(id);
+            });
         this.writer.writeArray(""); // End of list
     }
 
     /***************************************************************************
 
         Must return list of all channels stored in this node.
 
-        Returns:
-            list of channel names
+        Params:
+            value_getter_dg = The delegate that is called with the list of
+                              channel names.
 
     ***************************************************************************/
 
-    abstract protected Const!(char[][]) getChannelsIds ( );
+    abstract protected void getChannelsIds (
+        scope void delegate ( const(void)[] ) value_getter_dg );
 }
diff --git a/src/dhtproto/node/request/GetNumConnections.d b/src/dhtproto/node/request/GetNumConnections.d
@@ -78,24 +78,30 @@ public abstract scope class GetNumConnections : DhtCommand
 
     final override protected void handleRequest ( )
     {
-        auto data = this.getConnectionsData();
-
-        this.writer.write(DhtConst.Status.E.Ok);
-
-        // TODO: is there a need to send the addr/port? surely the client knows this anyway?
-        this.writer.writeArray(data.address);
-        this.writer.write(data.port);
-        this.writer.write(data.num_conns);
+        this.getConnectionsData(
+            ( NumConnectionsData data )
+            {
+                this.writer.write(DhtConst.Status.E.Ok);
+
+                // TODO: is there a need to send the addr/port?
+                // surely the client knows this anyway?
+                this.writer.writeArray(data.address);
+                this.writer.write(data.port);
+                this.writer.write(data.num_conns);
+            }
+        );
     }
 
     /***************************************************************************
 
-        Must return total num_conns of established connections to this node.
+        Gets the total num_conns of established connections to this node.
 
-        Returns:
-            metadata that includes number of established connections
+        Params:
+            value_getter_dg = The delegate that is called with the metadata
+                              that includes number of established connections.
 
     ***************************************************************************/
 
-    abstract protected NumConnectionsData getConnectionsData ( );
+    abstract protected void getConnectionsData (
+        scope void delegate ( NumConnectionsData ) value_getter_dg );
 }
diff --git a/src/dhtproto/node/request/GetResponsibleRange.d b/src/dhtproto/node/request/GetResponsibleRange.d
@@ -63,23 +63,26 @@ public abstract scope class GetResponsibleRange : DhtCommand
 
     final override protected void handleRequest ( )
     {
-        this.writer.write(DhtConst.Status.E.Ok);
-        hash_t min, max;
-        this.getRangeLimits(min, max);
-        this.writer.write(min);
-        this.writer.write(max);
+        this.getRangeLimits(
+            ( hash_t min, hash_t max )
+            {
+                this.writer.write(DhtConst.Status.E.Ok);
+                this.writer.write(min);
+                this.writer.write(max);
+            });
     }
 
     /***************************************************************************
 
-        Must return minimum and maximum allowed hash value this node
+        Get the minimum and maximum allowed hash value this node
         is responsible for.
 
         Params:
-            min = minimal allowed hash
-            max = maximal allowed hash
+            value_getter_dg = The delegate that is called with the minimum and
+                              the maximum allowed hashes.
 
     ***************************************************************************/
 
-    abstract protected void getRangeLimits ( out hash_t min, out hash_t max );
+    abstract protected void getRangeLimits (
+        scope void delegate ( hash_t min, hash_t max ) value_getter_dg );
 }
diff --git a/src/dhtproto/node/request/GetSize.d b/src/dhtproto/node/request/GetSize.d
@@ -51,7 +51,7 @@ public abstract scope class GetSize : DhtCommand
 
     /***************************************************************************
 
-        Payload structs that holds requested metadata 
+        Payload structs that holds requested metadata
 
     ***************************************************************************/
 
@@ -79,25 +79,30 @@ public abstract scope class GetSize : DhtCommand
 
     final override protected void handleRequest ( )
     {
-        auto data = this.getSizeData();
-
-        this.writer.write(DhtConst.Status.E.Ok);
-
-        // TODO: is there a need to send the addr/port? surely the client knows this anyway?
-        this.writer.writeArray(data.address);
-        this.writer.write(data.port);
-        this.writer.write(data.records);
-        this.writer.write(data.bytes);
+        this.getSizeData(
+            ( SizeData data )
+            {
+                this.writer.write(DhtConst.Status.E.Ok);
+
+                // TODO: is there a need to send the addr/port?
+                // surely the client knows this anyway?
+                this.writer.writeArray(data.address);
+                this.writer.write(data.port);
+                this.writer.write(data.records);
+                this.writer.write(data.bytes);
+            });
     }
 
     /***************************************************************************
 
-        Must return aggregated size of all channels.
+        Gets the aggregated size of all channels.
 
-        Returns:
-            metadata that includes the size
+        Params:
+            value_getter_dg = The delegate that is called with the metadata
+                              that includes the size.
 
     ***************************************************************************/
 
-    abstract protected SizeData getSizeData ( );
+    abstract protected void getSizeData (
+        scope void delegate ( SizeData ) value_getter_dg );
 }
diff --git a/src/fakedht/request/Get.d b/src/fakedht/request/Get.d
@@ -50,17 +50,18 @@ public scope class Get : Protocol.Get
         Params:
             channel_name = name of channel to query
             key = key of record to find
-
-        Returns:
-            value of queried record, empty array if not found
+            value_getter_dg = The delegate that is called with the value.
 
     ***************************************************************************/
 
-    override protected Const!(void)[] getValue ( cstring channel_name, cstring key )
+    override protected void getValue ( cstring channel_name, cstring key,
+        scope void delegate ( const(void)[] ) value_getter_dg )
     {
         auto channel = global_storage.get(channel_name);
-        if (channel is null)
-            return null;
-        return channel.get(key);
+
+        if (channel !is null)
+        {
+            value_getter_dg(channel.get(key));
+        }
     }
 }
diff --git a/src/fakedht/request/GetChannelSize.d b/src/fakedht/request/GetChannelSize.d
@@ -49,15 +49,17 @@ public scope class GetChannelSize : Protocol.GetChannelSize
 
         Params:
             channel_name = name of channel to be queried
+            value_getter_dg = The delegate that is called with the channel data.
 
     ***************************************************************************/
 
-    override protected ChannelSizeData getChannelData ( cstring channel_name )
+    override protected void getChannelData ( cstring channel_name,
+        scope void delegate ( ChannelSizeData ) value_getter_dg )
     {
         ChannelSizeData result;
         auto channel = global_storage.get(channel_name);
         if (channel !is null)
             channel.countSize(result.records, result.bytes);
-        return result;
+        value_getter_dg(result);
     }
 }
diff --git a/src/fakedht/request/GetChannels.d b/src/fakedht/request/GetChannels.d
@@ -46,13 +46,18 @@ public scope class GetChannels : Protocol.GetChannels
 
         Must return list of all channels stored in this node.
 
-        Returns:
-            list of channel names
+        Params:
+            value_getter_dg = The delegate that is called with the list of
+                              channel names.
 
     ***************************************************************************/
 
-    override protected Const!(char[][]) getChannelsIds ( )
+    override protected void getChannelsIds (
+        scope void delegate ( const(void)[] ) value_getter_dg )
     {
-        return global_storage.getChannelList();
+        foreach (ref id; global_storage.getChannelList())
+        {
+            value_getter_dg(id);
+        }
     }
 }
diff --git a/src/fakedht/request/GetNumConnections.d b/src/fakedht/request/GetNumConnections.d
@@ -42,17 +42,18 @@ public scope class GetNumConnections : Protocol.GetNumConnections
 
     /***************************************************************************
 
-        Must return total num_conns of established connections to this node.
+        Gets the total num_conns of established connections to this node.
 
-        Returns:
-            metadata that includes number of established connections
+        Params:
+            value_getter_dg = The delegate that is called with the metadata
+                              that includes number of established connections.
 
     ***************************************************************************/
 
-    override protected NumConnectionsData getConnectionsData ( )
+    override protected void getConnectionsData (
+        scope void delegate ( NumConnectionsData ) /* value_getter_dg */ )
     {
         enforce(false,
             "GetNumConnections is not supported by the fake DHT node");
-        return NumConnectionsData.init;
     }
 }
diff --git a/src/fakedht/request/GetResponsibleRange.d b/src/fakedht/request/GetResponsibleRange.d
@@ -41,7 +41,7 @@ public scope class GetResponsibleRange : Protocol.GetResponsibleRange
 
     /***************************************************************************
 
-        Must return minimum and maximum allowed hash value this node
+        Get the return minimum and maximum allowed hash value this node
         is responsible for.
 
         Params:
@@ -50,9 +50,9 @@ public scope class GetResponsibleRange : Protocol.GetResponsibleRange
 
     ***************************************************************************/
 
-    override protected void getRangeLimits ( out hash_t min, out hash_t max )
+    override protected void getRangeLimits (
+        scope void delegate ( hash_t min, hash_t max ) value_getter_dg )
     {
-        min = hash_t.min;
-        max = hash_t.max;
+        value_getter_dg(hash_t.min, hash_t.max);
     }
 }
diff --git a/src/fakedht/request/GetSize.d b/src/fakedht/request/GetSize.d
@@ -42,14 +42,16 @@ public scope class GetSize : Protocol.GetSize
 
     /***************************************************************************
 
-        Must return aggregated size of all channels.
+        Gets the aggregated size of all channels.
 
-        Returns:
-            metadata that includes the size
+        Params:
+            value_getter_dg = The delegate that is called with the metadata
+                              that includes the size.
 
     ***************************************************************************/
 
-    override protected SizeData getSizeData ( )
+    override protected void getSizeData (
+        scope void delegate ( SizeData ) value_getter_dg )
     {
         SizeData result;
         auto channels = global_storage.getChannelList();
@@ -62,6 +64,6 @@ public scope class GetSize : Protocol.GetSize
             result.bytes += bytes;
         }
 
-        return result;
+        value_getter_dg(result);
     }
 }