Make the DF suspend lock recursive, and add RPC calls for batch suspend.

The idea is that if you have to execute many RPC calls, it is
faster to suspend once. The service class takes care to auto-resume
in the destructor in case the client just disappears.

library/Core.cpp

@@ -98,6 +98,20 @@ struct Core::Cond
     bool predicate;
 };
 
+struct Core::Private
+{
+    tthread::mutex AccessMutex;
+    tthread::mutex StackMutex;
+    std::stack<Core::Cond*> suspended_tools;
+    Core::Cond core_cond;
+    thread::id df_suspend_thread;
+    int df_suspend_depth;
+
+    Private() {
+        df_suspend_depth = 0;
+    }
+};
+
 void cheap_tokenise(string const& input, vector<string> &output)
 {
     string *cur = NULL;
@@ -550,6 +564,8 @@ void fIOthread(void * iodata)
 
 Core::Core()
 {
+    d = new Private();
+
     // init the console. This must be always the first step!
     plug_mgr = 0;
     vif = 0;
@@ -559,10 +575,6 @@ Core::Core()
     started = false;
     memset(&(s_mods), 0, sizeof(s_mods));
 
-    // create mutex for syncing with interactive tasks
-    AccessMutex = 0;
-    StackMutex = 0;
-    core_cond = 0;
     // set up hotkey capture
     hotkey_set = false;
     HotkeyMutex = 0;
@@ -661,10 +673,7 @@ bool Core::Init()
     df::global::InitGlobals();
 
     // create mutex for syncing with interactive tasks
-    StackMutex = new mutex();
-    AccessMutex = new mutex();
     misc_data_mutex=new mutex();
-    core_cond = new Core::Cond();
     cerr << "Initializing Plugins.\n";
     // create plugin manager
     plug_mgr = new PluginManager(this);
@@ -757,22 +766,49 @@ void *Core::GetData( std::string key )
 
 void Core::Suspend()
 {
-    Core::Cond * nc = new Core::Cond();
+    auto tid = this_thread::get_id();
+
+    // If recursive, just increment the count
+    {
+        lock_guard<mutex> lock(d->AccessMutex);
+
+        if (d->df_suspend_depth > 0 && d->df_suspend_thread == tid)
+        {
+            d->df_suspend_depth++;
+            return;
+        }
+    }
+
     // put the condition on a stack
-    StackMutex->lock();
-        suspended_tools.push(nc);
-    StackMutex->unlock();
+    Core::Cond *nc = new Core::Cond();
+
+    {
+        lock_guard<mutex> lock2(d->StackMutex);
+
+        d->suspended_tools.push(nc);
+    }
+
     // wait until Core::Update() wakes up the tool
-    AccessMutex->lock();
-        nc->Lock(AccessMutex);
-    AccessMutex->unlock();
+    {
+        lock_guard<mutex> lock(d->AccessMutex);
+
+        nc->Lock(&d->AccessMutex);
+
+        assert(d->df_suspend_depth == 0);
+        d->df_suspend_thread = tid;
+        d->df_suspend_depth = 1;
+    }
 }
 
 void Core::Resume()
 {
-    AccessMutex->lock();
-        core_cond->Unlock();
-    AccessMutex->unlock();
+    auto tid = this_thread::get_id();
+    lock_guard<mutex> lock(d->AccessMutex);
+
+    assert(d->df_suspend_depth > 0 && d->df_suspend_thread == tid);
+
+    if (--d->df_suspend_depth == 0)
+        d->core_cond.Unlock();
 }
 
 int Core::TileUpdate()
@@ -827,21 +863,24 @@ int Core::Update()
 
     // wake waiting tools
     // do not allow more tools to join in while we process stuff here
-    StackMutex->lock();
-    while (!suspended_tools.empty())
+    lock_guard<mutex> lock_stack(d->StackMutex);
+
+    while (!d->suspended_tools.empty())
     {
-        Core::Cond * nc = suspended_tools.top();
-        suspended_tools.pop();
-        AccessMutex->lock();
+        Core::Cond * nc = d->suspended_tools.top();
+        d->suspended_tools.pop();
+
+        lock_guard<mutex> lock(d->AccessMutex);
         // wake tool
         nc->Unlock();
         // wait for tool to wake us
-            core_cond->Lock(AccessMutex);
-        AccessMutex->unlock();
+        d->core_cond.Lock(&d->AccessMutex);
+        // verify
+        assert(d->df_suspend_depth == 0);
         // destroy condition
         delete nc;
     }
-    StackMutex->unlock();
+
     return 0;
 };
 

library/RemoteServer.cpp

@@ -64,11 +64,21 @@ using dfproto::CoreTextFragment;
 using google::protobuf::MessageLite;
 
 CoreService::CoreService() {
+    suspend_depth = 0;
+
     // These 2 methods must be first, so that they get id 0 and 1
     addMethod("BindMethod", &CoreService::BindMethod);
     addMethod("RunCommand", &CoreService::RunCommand);
 
     // Add others here:
+    addMethod("CoreSuspend", &CoreService::CoreSuspend);
+    addMethod("CoreResume", &CoreService::CoreResume);
+}
+
+CoreService::~CoreService()
+{
+    while (suspend_depth-- > 0)
+        Core::getInstance().Resume();
 }
 
 command_result CoreService::BindMethod(color_ostream &stream,
@@ -107,6 +117,23 @@ command_result CoreService::RunCommand(color_ostream &stream,
     return Core::getInstance().plug_mgr->InvokeCommand(stream, cmd, args);
 }
 
+command_result CoreService::CoreSuspend(color_ostream &stream, const EmptyMessage*, IntMessage *cnt)
+{
+    Core::getInstance().Suspend();
+    cnt->set_value(++suspend_depth);
+    return CR_OK;
+}
+
+command_result CoreService::CoreResume(color_ostream &stream, const EmptyMessage*, IntMessage *cnt)
+{
+    if (suspend_depth <= 0)
+        return CR_WRONG_USAGE;
+
+    Core::getInstance().Resume();
+    cnt->set_value(--suspend_depth);
+    return CR_OK;
+}
+
 RPCService::RPCService()
 {
     owner = NULL;

library/include/Core.h

@@ -141,24 +141,28 @@ namespace DFHack
         DFHack::Console con;
 
         Core();
+
+        class Private;
+        Private *d;
+
         bool Init();
         int Update (void);
         int TileUpdate (void);
         int Shutdown (void);
         int SDL_Event(SDL::Event* event);
         bool ncurses_wgetch(int in, int & out);
+
         Core(Core const&);              // Don't Implement
         void operator=(Core const&);    // Don't implement
+
         // report error to user while failing
         void fatal (std::string output, bool will_deactivate);
+
         // 1 = fatal failure
         bool errorstate;
         // regulate access to DF
         struct Cond;
-        tthread::mutex * AccessMutex;
-        tthread::mutex * StackMutex;
-        std::stack < Core::Cond * > suspended_tools;
-        Core::Cond * core_cond;
+
         // FIXME: shouldn't be kept around like this
         DFHack::VersionInfoFactory * vif;
         // Module storage

library/include/RemoteClient.h

@@ -34,6 +34,8 @@ distribution.
 namespace  DFHack
 {
     using dfproto::EmptyMessage;
+    using dfproto::IntMessage;
+    using dfproto::StringMessage;
 
     enum command_result
     {

library/include/RemoteServer.h

@@ -189,14 +189,20 @@ namespace  DFHack
     };
 
     class CoreService : public RPCService {
+        int suspend_depth;
     public:
         CoreService();
+        ~CoreService();
 
         command_result BindMethod(color_ostream &stream,
                                   const dfproto::CoreBindRequest *in,
                                   dfproto::CoreBindReply *out);
         command_result RunCommand(color_ostream &stream,
                                   const dfproto::CoreRunCommandRequest *in);
+
+        // For batching
+        command_result CoreSuspend(color_ostream &stream, const EmptyMessage*, IntMessage *cnt);
+        command_result CoreResume(color_ostream &stream, const EmptyMessage*, IntMessage *cnt);
     };
 
     class DFHACK_EXPORT ServerConnection {

library/proto/CoreProtocol.proto

@@ -45,6 +45,14 @@ message CoreErrorNotification {
 
 message EmptyMessage {}
 
+message IntMessage {
+    required int32 value = 1;
+}
+
+message StringMessage {
+    required string value = 1;
+}
+
 message CoreBindRequest {
     required string method = 1;
     required string input_msg = 2;