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event: add function BlockingCall()

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Replaces io_thread_call().  This approach is more generic and easier
to use due to std::function.
This commit is contained in:
Max Kellermann
2013-08-07 22:42:45 +02:00
parent 9ab0a1f5f1
commit 018f4155eb
6 changed files with 130 additions and 108 deletions
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1
Makefile.am
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@@ -304,6 +304,7 @@ libevent_a_SOURCES = \
src/event/FullyBufferedSocket.cxx src/event/FullyBufferedSocket.hxx \
src/event/MultiSocketMonitor.cxx src/event/MultiSocketMonitor.hxx \
src/event/ServerSocket.cxx src/event/ServerSocket.hxx \
src/event/Call.hxx src/event/Call.cxx \
src/event/Loop.cxx src/event/Loop.hxx
# PCM library

50
src/IOThread.cxx
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@@ -115,53 +115,3 @@ io_thread_inside(void)
{
return io.thread != NULL && g_thread_self() == io.thread;
}
struct call_data {
GThreadFunc function;
gpointer data;
bool done;
gpointer result;
};
static gboolean
io_thread_call_func(gpointer _data)
{
struct call_data *data = (struct call_data *)_data;
gpointer result = data->function(data->data);
io.mutex.lock();
data->done = true;
data->result = result;
io.cond.broadcast();
io.mutex.unlock();
return false;
}
gpointer
io_thread_call(GThreadFunc function, gpointer _data)
{
assert(io.thread != NULL);
if (io_thread_inside())
/* we're already in the I/O thread - no
synchronization needed */
return function(_data);
struct call_data data = {
function,
_data,
false,
nullptr,
};
io.loop->AddIdle(io_thread_call_func, &data);
io.mutex.lock();
while (!data.done)
io.cond.wait(io.mutex);
io.mutex.unlock();
return data.result;
}

6
src/IOThread.hxx
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@@ -62,10 +62,4 @@ gcc_pure
bool
io_thread_inside(void);
/**
* Call a function synchronously in the I/O thread.
*/
gpointer
io_thread_call(GThreadFunc function, gpointer data);
#endif

72
src/event/Call.cxx Normal file
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@@ -0,0 +1,72 @@
/*
* Copyright (C) 2003-2013 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "config.h"
#include "Call.hxx"
#include "Loop.hxx"
#include "DeferredMonitor.hxx"
#include "thread/Mutex.hxx"
#include "thread/Cond.hxx"
#include "gcc.h"
#include <assert.h>
class BlockingCallMonitor final : DeferredMonitor {
const std::function<void()> f;
Mutex mutex;
Cond cond;
bool done;
public:
BlockingCallMonitor(EventLoop &_loop, std::function<void()> &&_f)
:DeferredMonitor(_loop), f(std::move(_f)), done(false) {}
void Run() {
assert(!done);
Schedule();
mutex.lock();
while (!done)
cond.wait(mutex);
mutex.unlock();
}
private:
virtual void RunDeferred() override {
f();
}
};
void
BlockingCall(EventLoop &loop, std::function<void()> &&f)
{
if (loop.IsInside()) {
/* we're already inside the loop - we can simply call
the function */
f();
} else {
/* outside the EventLoop's thread - defer execution to
the EventLoop, wait for completion */
BlockingCallMonitor m(loop, std::move(f));
m.Run();
}
}

36
src/event/Call.hxx Normal file
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@@ -0,0 +1,36 @@
/*
* Copyright (C) 2003-2013 The Music Player Daemon Project
* http://www.musicpd.org
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#ifndef MPD_EVENT_CALL_HXX
#define MPD_EVENT_CALL_HXX
#include "check.h"
#include <functional>
class EventLoop;
/**
* Call the given function in the context of the #EventLoop, and wait
* for it to finish.
*/
void
BlockingCall(EventLoop &loop, std::function<void()> &&f);
#endif /* MAIN_NOTIFY_H */

73
src/input/CurlInputPlugin.cxx
View File

@@ -26,7 +26,7 @@
#include "Tag.hxx"
#include "IcyMetaDataParser.hxx"
#include "event/MultiSocketMonitor.hxx"
#include "event/Loop.hxx"
#include "event/Call.hxx"
#include "IOThread.hxx"
#include <assert.h>
@@ -252,19 +252,15 @@ input_curl_find_request(CURL *easy)
return NULL;
}
static gpointer
input_curl_resume(gpointer data)
static void
input_curl_resume(struct input_curl *c)
{
assert(io_thread_inside());
struct input_curl *c = (struct input_curl *)data;
if (c->paused) {
c->paused = false;
curl_easy_pause(c->easy, CURLPAUSE_CONT);
}
return NULL;
}
/**
@@ -358,21 +354,6 @@ input_curl_easy_add(struct input_curl *c, GError **error_r)
return true;
}
struct easy_add_params {
struct input_curl *c;
GError **error_r;
};
static gpointer
input_curl_easy_add_callback(gpointer data)
{
const struct easy_add_params *params =
(const struct easy_add_params *)data;
bool success = input_curl_easy_add(params->c, params->error_r);
return GUINT_TO_POINTER(success);
}
/**
* Call input_curl_easy_add() in the I/O thread. May be called from
* any thread. Caller must not hold a mutex.
@@ -383,14 +364,11 @@ input_curl_easy_add_indirect(struct input_curl *c, GError **error_r)
assert(c != NULL);
assert(c->easy != NULL);
struct easy_add_params params = {
c,
error_r,
};
gpointer result =
io_thread_call(input_curl_easy_add_callback, &params);
return GPOINTER_TO_UINT(result);
bool result;
BlockingCall(io_thread_get(), [c, error_r, &result](){
result = input_curl_easy_add(c, error_r);
});
return result;
}
/**
@@ -421,17 +399,6 @@ input_curl_easy_free(struct input_curl *c)
c->range = NULL;
}
static gpointer
input_curl_easy_free_callback(gpointer data)
{
struct input_curl *c = (struct input_curl *)data;
input_curl_easy_free(c);
curl.sockets->InvalidateSockets();
return NULL;
}
/**
* Frees the current "libcurl easy" handle, and everything associated
* with it.
@@ -441,7 +408,11 @@ input_curl_easy_free_callback(gpointer data)
static void
input_curl_easy_free_indirect(struct input_curl *c)
{
io_thread_call(input_curl_easy_free_callback, c);
BlockingCall(io_thread_get(), [c](){
input_curl_easy_free(c);
curl.sockets->InvalidateSockets();
});
assert(c->easy == NULL);
}
@@ -654,20 +625,14 @@ input_curl_init(const config_param &param,
return true;
}
static gpointer
curl_destroy_sources(gcc_unused gpointer data)
{
delete curl.sockets;
return NULL;
}
static void
input_curl_finish(void)
{
assert(curl.requests.empty());
io_thread_call(curl_destroy_sources, NULL);
BlockingCall(io_thread_get(), [](){
delete curl.sockets;
});
curl_multi_cleanup(curl.multi);
@@ -854,7 +819,11 @@ input_curl_read(struct input_stream *is, void *ptr, size_t size,
if (c->paused && curl_total_buffer_size(c) < CURL_RESUME_AT) {
c->base.mutex.unlock();
io_thread_call(input_curl_resume, c);
BlockingCall(io_thread_get(), [c](){
input_curl_resume(c);
});
c->base.mutex.lock();
}