File 0091-Avoid-livelock-in-driver-when-batching-commands.patch of Package erlang
From b901918e7616dd346bfeb3e3c22be608a27f8da4 Mon Sep 17 00:00:00 2001
From: Dan Gudmundsson <dgud@erlang.org>
Date: Tue, 21 Mar 2017 11:59:14 +0100
Subject: [PATCH] Avoid livelock in driver when batching commands
With a bad timing in wx:batch() the driver could get stuck
handling commands without ever checking for gui events.
Avoid that by exiting loop after the driver have done cond_wait a
couple of times.
---
lib/wx/c_src/wxe_impl.cpp | 28 +++++++++++++++++-----------
lib/wx/c_src/wxe_impl.h | 2 +-
lib/wx/examples/demo/demo.erl | 3 +++
lib/wx/src/wxe_master.erl | 10 ++++++++--
4 files changed, 29 insertions(+), 14 deletions(-)
diff --git a/lib/wx/c_src/wxe_impl.cpp b/lib/wx/c_src/wxe_impl.cpp
index 0d2da5d4a..05d56667a 100644
--- a/lib/wx/c_src/wxe_impl.cpp
+++ b/lib/wx/c_src/wxe_impl.cpp
@@ -128,7 +128,7 @@ bool WxeApp::OnInit()
delayed_cleanup = new wxList;
wxe_ps_init2();
- // wxIdleEvent::SetMode(wxIDLE_PROCESS_SPECIFIED); // Hmm printpreview doesn't work in 2.9 with this
+ wxIdleEvent::SetMode(wxIDLE_PROCESS_SPECIFIED);
Connect(wxID_ANY, wxEVT_IDLE, (wxObjectEventFunction) (wxEventFunction) &WxeApp::idle);
Connect(CREATE_PORT, wxeEVT_META_COMMAND,(wxObjectEventFunction) (wxEventFunction) &WxeApp::newMemEnv);
@@ -200,7 +200,8 @@ void WxeApp::OnAssertFailure(const wxChar *file, int line, const wxChar *cfunc,
// Called by wx thread
void WxeApp::idle(wxIdleEvent& event) {
event.Skip(true);
- dispatch_cmds();
+ if(dispatch_cmds())
+ event.RequestMore();
}
/* ************************************************************
@@ -233,14 +234,15 @@ void handle_event_callback(ErlDrvPort port, ErlDrvTermData process)
}
}
-void WxeApp::dispatch_cmds()
+int WxeApp::dispatch_cmds()
{
+ int more = 0;
if(wxe_status != WXE_INITIATED)
- return;
+ return more;
recurse_level++;
// fprintf(stderr, "\r\ndispatch_normal %d\r\n", recurse_level);fflush(stderr);
wxe_queue->cb_start = 0;
- dispatch(wxe_queue);
+ more = dispatch(wxe_queue);
// fprintf(stderr, "\r\ndispatch_done %d\r\n", recurse_level);fflush(stderr);
recurse_level--;
@@ -262,12 +264,14 @@ void WxeApp::dispatch_cmds()
delete event;
}
}
+ return more;
}
int WxeApp::dispatch(wxeFifo * batch)
{
int ping = 0;
int blevel = 0;
+ int wait = 0; // Let event handling generate events sometime
wxeCommand *event;
erl_drv_mutex_lock(wxe_batch_locker_m);
while(true) {
@@ -275,10 +279,10 @@ int WxeApp::dispatch(wxeFifo * batch)
erl_drv_mutex_unlock(wxe_batch_locker_m);
switch(event->op) {
case WXE_BATCH_END:
- {--blevel; }
+ if(blevel>0) blevel--;
break;
case WXE_BATCH_BEGIN:
- {blevel++; }
+ blevel++;
break;
case WXE_DEBUG_PING:
// When in debugger we don't want to hang waiting for a BATCH_END
@@ -293,7 +297,7 @@ int WxeApp::dispatch(wxeFifo * batch)
memcpy(cb_buff, event->buffer, event->len);
}
event->Delete();
- return blevel;
+ return 1;
default:
if(event->op < OPENGL_START) {
// fprintf(stderr, " c %d (%d) \r\n", event->op, blevel);
@@ -307,13 +311,15 @@ int WxeApp::dispatch(wxeFifo * batch)
erl_drv_mutex_lock(wxe_batch_locker_m);
batch->Cleanup();
}
- if(blevel <= 0) {
+ if(blevel <= 0 || wait > 3) {
erl_drv_mutex_unlock(wxe_batch_locker_m);
- return blevel;
+ if(blevel > 0) return 1; // We are still in a batch but we can let wx check for events
+ else return 0;
}
// sleep until something happens
- //fprintf(stderr, "%s:%d sleep %d %d\r\n", __FILE__, __LINE__, batch->m_n, blevel);fflush(stderr);
+ // fprintf(stderr, "%s:%d sleep %d %d %d\r\n", __FILE__, __LINE__, batch->m_n, blevel, wait);fflush(stderr);
wxe_needs_signal = 1;
+ wait += 1;
while(batch->m_n == 0) {
erl_drv_cond_wait(wxe_batch_locker_c, wxe_batch_locker_m);
}
diff --git a/lib/wx/c_src/wxe_impl.h b/lib/wx/c_src/wxe_impl.h
index 57dac997a..68f5deb33 100644
--- a/lib/wx/c_src/wxe_impl.h
+++ b/lib/wx/c_src/wxe_impl.h
@@ -73,7 +73,7 @@ public:
void wxe_dispatch(wxeCommand& event);
void idle(wxIdleEvent& event);
- void dispatch_cmds();
+ int dispatch_cmds();
void dummy_close(wxEvent& Ev);
bool sendevent(wxEvent *event);
diff --git a/lib/wx/examples/demo/demo.erl b/lib/wx/examples/demo/demo.erl
index 8b7412017..0258202a6 100644
--- a/lib/wx/examples/demo/demo.erl
+++ b/lib/wx/examples/demo/demo.erl
@@ -243,6 +243,9 @@ handle_event(#wx{id = Id,
%% If you are going to printout mainly text it is easier if
%% you generate HTML code and use a wxHtmlEasyPrint
%% instead of using DCs
+
+ %% Printpreview doesn't work in >2.9 without this
+ wxIdleEvent:setMode(?wxIDLE_PROCESS_ALL),
Module = "ex_" ++ wxListBox:getStringSelection(State#state.selector) ++ ".erl",
HEP = wxHtmlEasyPrinting:new([{name, "Print"},
{parentWindow, State#state.win}]),
diff --git a/lib/wx/src/wxe_master.erl b/lib/wx/src/wxe_master.erl
index e17a3327a..913bf4d41 100644
--- a/lib/wx/src/wxe_master.erl
+++ b/lib/wx/src/wxe_master.erl
@@ -82,8 +82,14 @@ init_port(SilentStart) ->
%% Initalizes the opengl library
%%--------------------------------------------------------------------
init_opengl() ->
- GLLib = wxe_util:wxgl_dl(),
- wxe_util:call(?WXE_INIT_OPENGL, <<(list_to_binary(GLLib))/binary, 0:8>>).
+ case get(wx_init_opengl) of
+ true -> {ok, "already initialized"};
+ _ ->
+ GLLib = wxe_util:wxgl_dl(),
+ Res = wxe_util:call(?WXE_INIT_OPENGL, <<(list_to_binary(GLLib))/binary, 0:8>>),
+ element(1, Res) =:= ok andalso put(wx_init_opengl, true),
+ Res
+ end.
%%--------------------------------------------------------------------
%% Fetch early messages, hack to get start up args on mac
--
2.12.2
