From cef9a7a112a8322e2c6498021df59e4a8f7b5246 Mon Sep 17 00:00:00 2001
From: Alexey Melnichuk <mimir@newmail.ru>
Date: Tue, 4 Feb 2014 11:06:17 +0400
Subject: Add. `thread:alive()` method.

---
 .travis.yml         |  1 +
 README.md           | 18 ++++++++++++++
 lakefile            |  1 +
 src/llthread.c      | 69 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 test/test_alive.lua | 35 +++++++++++++++++++++++++++
 5 files changed, 124 insertions(+)
 create mode 100644 test/test_alive.lua

diff --git a/.travis.yml b/.travis.yml
index b6dc082..dc2ef16 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -56,6 +56,7 @@ script:
   - lua$LUA_SFX test_logger.lua
   - lua$LUA_SFX test_pass_cfunction.lua
   - lua$LUA_SFX test_load_llthreads2.lua
+  - lua$LUA_SFX test_alive.lua
 
 notifications:
   email:
diff --git a/README.md b/README.md
index ba38ebd..66e4d8b 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ This is full dropin replacement for [llthreads](https://github.com/Neopallium/lu
 ##Additional
 * thread:join() method support zero timeout to check if thread alive (does not work on Windows with pthreads)
 * thread:join() method support arbitrary timeout on Windows threads
+* thread:alive() method return whether the thread is alive (does not work on Windows with pthreads)
 * set_logger function allow logging errors (crash Lua VM) in current llthread's threads
 * thread:start() has additional parameter which control in which thread child Lua VM will be destroyed
 * allow pass cfunctions to child thread (e.g. to initialize Lua state)
@@ -89,5 +90,22 @@ llthreads.new([[
 ]], preload):start(true)
 ```
 
+### Wait while thread is alive
+``` Lua 
+local thread = require "llthreads".new[[
+  require "utils".sleep(5)
+  return 1
+]]
+thread:start()
+
+-- we can not use `thread:join(0)` because we can not call it twice
+-- so all returned vaules will be lost
+while thread:alive() do 
+  -- do some work
+end
+
+local ok, ret = thread:join() -- true, 1
+```
+
 [![Bitdeli Badge](https://d2weczhvl823v0.cloudfront.net/moteus/lua-llthreads2/trend.png)](https://bitdeli.com/free "Bitdeli Badge")
 
diff --git a/lakefile b/lakefile
index b7786b1..060035a 100644
--- a/lakefile
+++ b/lakefile
@@ -36,6 +36,7 @@ target('test', install, function()
   run_test('test_register_ffi.lua')
   run_test('test_logger.lua')
   run_test('test_pass_cfunction.lua')
+  run_test('test_alive.lua')
 
   if not test_summary() then
     quit("test fail")
diff --git a/src/llthread.c b/src/llthread.c
index ac485e3..0ffa727 100644
--- a/src/llthread.c
+++ b/src/llthread.c
@@ -457,6 +457,35 @@ static int llthread_join(llthread_t *this, join_timeout_t timeout) {
   }
 }
 
+static int llthread_alive(llthread_t *this) {
+  llthread_validate(this);
+
+  if(IS(this, JOINED)){
+    return JOIN_OK;
+  } else{
+#ifndef USE_PTHREAD
+  DWORD ret = 0;
+  if(INVALID_THREAD == this->thread) return JOIN_OK;
+  ret = WaitForSingleObject( this->thread, 0 );
+  if( ret == WAIT_OBJECT_0) return JOIN_OK;
+  if( ret == WAIT_TIMEOUT ) return JOIN_ETIMEDOUT;
+  return JOIN_FAIL;
+#else
+  int rc = pthread_kill(this->thread, 0);
+  if(rc == 0){ /* still alive */
+    return JOIN_ETIMEDOUT;
+  }
+
+  if(rc != ESRCH){ 
+    /*@fixme what else it can be ?*/
+    return rc;
+  }
+
+  return JOIN_OK;
+#endif
+  }
+}
+
 static llthread_t *llthread_create(lua_State *L, const char *code, size_t code_len) {
   llthread_t *this        = llthread_new();
   llthread_child_t *child = this->child;
@@ -592,6 +621,45 @@ static int l_llthread_join(lua_State *L) {
 
 }
 
+static int l_llthread_alive(lua_State *L) {
+  llthread_t *this = l_llthread_at(L, 1);
+  llthread_child_t *child = this->child;
+  int rc;
+
+  if(!IS(this, STARTED )) {
+    return fail(L, "Can't join a thread that hasn't be started.");
+  }
+  if( IS(this, DETACHED) && !IS(this, JOINABLE)) {
+    return fail(L, "Can't join a thread that has been detached.");
+  }
+  if( IS(this, JOINED  )) {
+    return fail(L, "Can't join a thread that has already been joined.");
+  }
+
+  /* join the thread. */
+  rc = llthread_alive(this);
+
+  if( rc == JOIN_ETIMEDOUT ){
+    lua_pushboolean(L, 1);
+    return 1;
+  }
+
+  if(rc == JOIN_OK){
+    lua_pushboolean(L, 0);
+    return 1;
+  }
+
+  {
+    char buf[ERROR_LEN];
+    strerror_r(errno, buf, ERROR_LEN);
+
+    /* llthread_cleanup_child(this); */
+
+    return fail(L, buf);
+  }
+
+}
+
 static int l_llthread_new(lua_State *L) {
   size_t lua_code_len; const char *lua_code = luaL_checklstring(L, 1, &lua_code_len);
   llthread_t **this = lutil_newudatap(L, llthread_t*, LLTHREAD_TAG);
@@ -605,6 +673,7 @@ static int l_llthread_new(lua_State *L) {
 static const struct luaL_Reg l_llthread_meth[] = {
   {"start",         l_llthread_start         },
   {"join",          l_llthread_join          },
+  {"alive",         l_llthread_alive         },
   {"__gc",          l_llthread_delete        },
 
   {NULL, NULL}
diff --git a/test/test_alive.lua b/test/test_alive.lua
new file mode 100644
index 0000000..ecce163
--- /dev/null
+++ b/test/test_alive.lua
@@ -0,0 +1,35 @@
+local llthreads = require"llthreads"
+local utils     = require "utils"
+local sleep     = utils.sleep
+
+local include = utils.thread_init .. [[
+local llthreads = require"llthreads"
+local sleep = require "utils".sleep
+]]
+
+local thread = llthreads.new(include .. [[
+  sleep(5)
+  return 1,2,3
+]])
+
+assert(nil == thread:alive())
+
+thread:start()
+
+assert(true == thread:alive())
+
+for i = 1, 10 do
+  if not thread:alive() then break end
+  sleep(1)
+end
+
+assert(false == thread:alive())
+
+local ok,a,b,c = thread:join(0)
+assert(ok == true)
+assert(a == 1)
+assert(b == 2)
+assert(c == 3)
+
+print("Done!")
+
-- 
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