Introduce async write interface in the TLS.

Wire it in all the way up and in to proton.
The implementation is still synchronous.

7 files changed, 45 insertions, 6 deletions

diff --git a/searchlib/src/vespa/searchlib/common/CMakeLists.txt b/searchlib/src/vespa/searchlib/common/CMakeLists.txt
index b1f71303449..f9db738528c 100644
--- a/searchlib/src/vespa/searchlib/common/CMakeLists.txt
+++ b/searchlib/src/vespa/searchlib/common/CMakeLists.txt
@@ -13,6 +13,7 @@ vespa_add_library(searchlib_common OBJECT
     featureset.cpp
     fileheadercontext.cpp
     foregroundtaskexecutor.cpp
+    gatecallback.cpp
     growablebitvector.cpp
     indexmetainfo.cpp
     location.cpp
diff --git a/searchlib/src/vespa/searchlib/common/gatecallback.cpp b/searchlib/src/vespa/searchlib/common/gatecallback.cpp
new file mode 100644
index 00000000000..a853909be71
--- /dev/null
+++ b/searchlib/src/vespa/searchlib/common/gatecallback.cpp
@@ -0,0 +1,12 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "gatecallback.h"
+#include <vespa/vespalib/util/sync.h>
+
+namespace search {
+
+GateCallback::~GateCallback() {
+    _gate.countDown();
+}
+
+}
diff --git a/searchlib/src/vespa/searchlib/common/gatecallback.h b/searchlib/src/vespa/searchlib/common/gatecallback.h
new file mode 100644
index 00000000000..1e85d796089
--- /dev/null
+++ b/searchlib/src/vespa/searchlib/common/gatecallback.h
@@ -0,0 +1,24 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+#pragma once
+
+#include "idestructorcallback.h"
+
+namespace vespalib { class Gate; }
+
+namespace search {
+
+class GateCallback : public IDestructorCallback {
+public:
+    GateCallback(vespalib::Gate & gate) : _gate(gate) {}
+    ~GateCallback() override;
+private:
+    vespalib::Gate & _gate;
+};
+
+class IgnoreCallback : public IDestructorCallback {
+public:
+    IgnoreCallback() { }
+    ~IgnoreCallback() override = default;
+};
+
+} // namespace search
diff --git a/searchlib/src/vespa/searchlib/common/idestructorcallback.h b/searchlib/src/vespa/searchlib/common/idestructorcallback.h
index 4c42f68f0e4..77adba7a4cc 100644
--- a/searchlib/src/vespa/searchlib/common/idestructorcallback.h
+++ b/searchlib/src/vespa/searchlib/common/idestructorcallback.h
@@ -3,8 +3,7 @@
 
 #include <memory>
 
-namespace search
-{
+namespace search {
 
 /**
  * Interface for class that performs a callback when instance is
@@ -17,7 +16,7 @@ class IDestructorCallback
 {
 public:
     using SP = std::shared_ptr<IDestructorCallback>;
-    virtual ~IDestructorCallback() { }
+    virtual ~IDestructorCallback() = default;
 };
 
 } // namespace search
diff --git a/searchlib/src/vespa/searchlib/transactionlog/common.h b/searchlib/src/vespa/searchlib/transactionlog/common.h
index 65ef8f363c0..db8b9727daa 100644
--- a/searchlib/src/vespa/searchlib/transactionlog/common.h
+++ b/searchlib/src/vespa/searchlib/transactionlog/common.h
@@ -2,6 +2,7 @@
 #pragma once
 
 #include <vespa/searchlib/common/serialnum.h>
+#include <vespa/searchlib/common/idestructorcallback.h>
 #include <vespa/vespalib/objects/nbostream.h>
 #include <vespa/vespalib/util/buffer.h>
 
@@ -90,8 +91,9 @@ int makeDirectory(const char * dir);
 
 class Writer {
 public:
+    using DoneCallback = std::shared_ptr<IDestructorCallback>;
     virtual ~Writer() { }
-    virtual void commit(const vespalib::string & domainName, const Packet & packet) = 0;
+    virtual void commit(const vespalib::string & domainName, const Packet & packet, DoneCallback done) = 0;
 };
 
 }
diff --git a/searchlib/src/vespa/searchlib/transactionlog/translogserver.cpp b/searchlib/src/vespa/searchlib/transactionlog/translogserver.cpp
index ca17457bdb9..e793aafd38f 100644
--- a/searchlib/src/vespa/searchlib/transactionlog/translogserver.cpp
+++ b/searchlib/src/vespa/searchlib/transactionlog/translogserver.cpp
@@ -453,8 +453,9 @@ void TransLogServer::domainStatus(FRT_RPCRequest *req)
     }
 }
 
-void TransLogServer::commit(const vespalib::string & domainName, const Packet & packet)
+void TransLogServer::commit(const vespalib::string & domainName, const Packet & packet, DoneCallback done)
 {
+    (void) done;
     Domain::SP domain(findDomain(domainName));
     if (domain) {
         domain->commit(packet);
diff --git a/searchlib/src/vespa/searchlib/transactionlog/translogserver.h b/searchlib/src/vespa/searchlib/transactionlog/translogserver.h
index 92832786059..c12e37dd1c8 100644
--- a/searchlib/src/vespa/searchlib/transactionlog/translogserver.h
+++ b/searchlib/src/vespa/searchlib/transactionlog/translogserver.h
@@ -31,7 +31,7 @@ public:
     virtual ~TransLogServer();
     DomainStats getDomainStats() const;
 
-    void commit(const vespalib::string & domainName, const Packet & packet) override;
+    void commit(const vespalib::string & domainName, const Packet & packet, DoneCallback done) override;
 
 
     class Session