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// Copyright 2022 Benjamin Barenblat
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.
#include <getopt.h>
#include <pulse/def.h>
#include <pulse/error.h>
#include <pulse/introspect.h>
#include <pulse/volume.h>
#include <signal.h>
#include <unistd.h>
#include <iomanip>
#include <ios>
#include <iostream>
#include <locale>
#include <string>
#include <string_view>
#include "pulse.h"
namespace {
constexpr std::string_view kShortUsage = "Usage: pavmon SINK_NAME\n";
constexpr std::string_view kHelp = R"(
Monitor the volume level of a PulseAudio sink, printing a new line each time it
changes.
Options:
--help display this help and exit
--version display version information and exit
)";
constexpr std::string_view kAskForHelp =
"Try \"pavmon --help\" for more information.\n";
constexpr std::string_view kVersionInfo = R"(pavmon 1.0.0
Copyright 2022 Benjamin Barenblat
Licensed under the Apache License, Version 2.0
)";
enum {
kHelpLongOption = 128,
kVersionLongOption,
};
void GetAndPrintVolume(const std::string& sink_name, pulse::PollMainLoop& loop,
pulse::Context& ctx) noexcept {
ctx.GetSinkInfo(
sink_name.c_str(),
[&]() noexcept {
std::clog << "pavmon: failed to get volume" << std::endl;
loop.Quit(1);
},
[&](const pa_sink_info& info) noexcept {
if (info.mute) {
std::cout << "muted (";
}
std::cout << std::fixed << std::setprecision(1)
<< pa_sw_volume_to_dB(pa_cvolume_avg(&info.volume)) << " dB";
if (info.mute) {
std::cout << ')';
}
std::cout << std::endl;
});
}
void SubscribeToEvents(const std::string& sink_name, pulse::PollMainLoop& loop,
pulse::Context& ctx) noexcept {
ctx.Subscribe(
PA_SUBSCRIPTION_MASK_SINK,
[&]() noexcept {
std::clog << "pavmon: failed to subscribe to events" << std::endl;
loop.Quit(1);
},
[&](pa_subscription_event_type_t) noexcept {
GetAndPrintVolume(sink_name, loop, ctx);
});
}
} // namespace
int main(int argc, char* argv[]) {
std::locale loc("");
std::locale::global(loc);
std::cin.imbue(loc);
std::cout.imbue(loc);
std::cerr.imbue(loc);
std::clog.imbue(loc);
std::wcin.imbue(loc);
std::wcout.imbue(loc);
std::wcerr.imbue(loc);
std::wclog.imbue(loc);
std::ios_base::sync_with_stdio(false);
static option long_options[] = {
{"help", no_argument, nullptr, kHelpLongOption},
{"version", no_argument, nullptr, kVersionLongOption},
{nullptr, 0, nullptr, 0},
};
while (true) {
int c = getopt_long(argc, argv, "", long_options, /*longindex=*/nullptr);
if (c == -1) {
break;
}
switch (c) {
case kHelpLongOption:
std::cout << kShortUsage << kHelp;
return 0;
case kVersionLongOption:
std::cout << kVersionInfo;
return 0;
case '?':
std::clog << kAskForHelp;
return 1;
default:
std::clog << "Internal error; please report.\n";
return 1;
}
}
if (optind != argc - 1) {
std::clog << kShortUsage << kAskForHelp;
return 1;
}
std::string sink_name = argv[1];
pulse::PollMainLoop loop;
loop.HandleSignals();
auto quit_on_signal = [&]() noexcept { loop.Quit(0); };
pulse::SignalEventSource quit_on_sigterm(SIGTERM, quit_on_signal);
pulse::SignalEventSource quit_on_sigint(SIGINT, quit_on_signal);
pulse::PropertyList proplist;
proplist.Set(PA_PROP_APPLICATION_NAME, "PulseAudio volume monitor");
proplist.Set(PA_PROP_APPLICATION_ID, "pavmon");
proplist.Set(PA_PROP_APPLICATION_VERSION, "1.0.0");
proplist.Set(PA_PROP_APPLICATION_PROCESS_ID, std::to_string(getpid()));
if (const char* user = getlogin(); user != nullptr) {
proplist.Set(PA_PROP_APPLICATION_PROCESS_USER, user);
}
// TODO(bbarenblat@gmail.com): More of these?
pulse::Context ctx("PulseAudio volume meter", proplist, loop);
ctx.Connect(PA_CONTEXT_NOFAIL, [&](pa_context_state_t state) noexcept {
switch (state) {
case PA_CONTEXT_UNCONNECTED:
case PA_CONTEXT_CONNECTING:
case PA_CONTEXT_AUTHORIZING:
case PA_CONTEXT_SETTING_NAME:
break;
case PA_CONTEXT_READY:
GetAndPrintVolume(sink_name, loop, ctx);
SubscribeToEvents(sink_name, loop, ctx);
break;
case PA_CONTEXT_TERMINATED:
loop.Quit(0);
break;
case PA_CONTEXT_FAILED:
default:
std::clog << "pavmon: failed to connect to PulseAudio" << std::endl;
loop.Quit(1);
break;
}
});
return loop.Run();
}
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