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dexed/JuceLibraryCode/modules/juce_events/interprocess/juce_ConnectedChildProcess.cpp

265 lines
8.3 KiB

/*
==============================================================================
This file is part of the JUCE library.
Copyright (c) 2013 - Raw Material Software Ltd.
Permission is granted to use this software under the terms of either:
a) the GPL v2 (or any later version)
b) the Affero GPL v3
Details of these licenses can be found at: www.gnu.org/licenses
JUCE 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.
------------------------------------------------------------------------------
To release a closed-source product which uses JUCE, commercial licenses are
available: visit www.juce.com for more information.
==============================================================================
*/
enum { magicMastSlaveConnectionHeader = 0x712baf04 };
static const char* startMessage = "__ipc_st";
static const char* killMessage = "__ipc_k_";
static const char* pingMessage = "__ipc_p_";
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enum { specialMessageSize = 8, defaultTimeoutMs = 8000 };
static String getCommandLinePrefix (const String& commandLineUniqueID)
{
return "--" + commandLineUniqueID + ":";
}
//==============================================================================
// This thread sends and receives ping messages every second, so that it
// can find out if the other process has stopped running.
struct ChildProcessPingThread : public Thread,
private AsyncUpdater
{
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ChildProcessPingThread (int timeout) : Thread ("IPC ping"), timeoutMs (timeout)
{
pingReceived();
}
static bool isPingMessage (const MemoryBlock& m) noexcept
{
return memcmp (m.getData(), pingMessage, specialMessageSize) == 0;
}
void pingReceived() noexcept { countdown = timeoutMs / 1000 + 1; }
void triggerConnectionLostMessage() { triggerAsyncUpdate(); }
virtual bool sendPingMessage (const MemoryBlock&) = 0;
virtual void pingFailed() = 0;
int timeoutMs;
private:
Atomic<int> countdown;
void handleAsyncUpdate() override { pingFailed(); }
void run() override
{
while (! threadShouldExit())
{
if (--countdown <= 0 || ! sendPingMessage (MemoryBlock (pingMessage, specialMessageSize)))
{
triggerConnectionLostMessage();
break;
}
wait (1000);
}
}
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JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (ChildProcessPingThread)
};
//==============================================================================
struct ChildProcessMaster::Connection : public InterprocessConnection,
private ChildProcessPingThread
{
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Connection (ChildProcessMaster& m, const String& pipeName, int timeout)
: InterprocessConnection (false, magicMastSlaveConnectionHeader),
ChildProcessPingThread (timeout),
owner (m)
{
if (createPipe (pipeName, timeoutMs))
startThread (4);
}
~Connection()
{
stopThread (10000);
}
private:
void connectionMade() override {}
void connectionLost() override { owner.handleConnectionLost(); }
bool sendPingMessage (const MemoryBlock& m) override { return owner.sendMessageToSlave (m); }
void pingFailed() override { connectionLost(); }
void messageReceived (const MemoryBlock& m) override
{
pingReceived();
if (m.getSize() != specialMessageSize || ! isPingMessage (m))
owner.handleMessageFromSlave (m);
}
ChildProcessMaster& owner;
JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Connection)
};
//==============================================================================
ChildProcessMaster::ChildProcessMaster() {}
ChildProcessMaster::~ChildProcessMaster()
{
if (connection != nullptr)
{
sendMessageToSlave (MemoryBlock (killMessage, specialMessageSize));
connection->disconnect();
connection = nullptr;
}
}
void ChildProcessMaster::handleConnectionLost() {}
bool ChildProcessMaster::sendMessageToSlave (const MemoryBlock& mb)
{
if (connection != nullptr)
return connection->sendMessage (mb);
jassertfalse; // this can only be used when the connection is active!
return false;
}
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bool ChildProcessMaster::launchSlaveProcess (const File& executable, const String& commandLineUniqueID, int timeoutMs)
{
connection = nullptr;
jassert (childProcess.kill());
const String pipeName ("p" + String::toHexString (Random().nextInt64()));
StringArray args;
args.add (executable.getFullPathName());
args.add (getCommandLinePrefix (commandLineUniqueID) + pipeName);
if (childProcess.start (args))
{
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connection = new Connection (*this, pipeName, timeoutMs <= 0 ? defaultTimeoutMs : timeoutMs);
if (connection->isConnected())
{
sendMessageToSlave (MemoryBlock (startMessage, specialMessageSize));
return true;
}
connection = nullptr;
}
return false;
}
//==============================================================================
struct ChildProcessSlave::Connection : public InterprocessConnection,
private ChildProcessPingThread
{
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Connection (ChildProcessSlave& p, const String& pipeName, int timeout)
: InterprocessConnection (false, magicMastSlaveConnectionHeader),
ChildProcessPingThread (timeout),
owner (p)
{
connectToPipe (pipeName, timeoutMs);
startThread (4);
}
~Connection()
{
stopThread (10000);
}
private:
ChildProcessSlave& owner;
void connectionMade() override {}
void connectionLost() override { owner.handleConnectionLost(); }
bool sendPingMessage (const MemoryBlock& m) override { return owner.sendMessageToMaster (m); }
void pingFailed() override { connectionLost(); }
void messageReceived (const MemoryBlock& m) override
{
pingReceived();
if (m.getSize() == specialMessageSize)
{
if (isPingMessage (m))
return;
if (memcmp (m.getData(), killMessage, specialMessageSize) == 0)
{
triggerConnectionLostMessage();
return;
}
if (memcmp (m.getData(), startMessage, specialMessageSize) == 0)
{
owner.handleConnectionMade();
return;
}
}
owner.handleMessageFromMaster (m);
}
JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Connection)
};
//==============================================================================
ChildProcessSlave::ChildProcessSlave() {}
ChildProcessSlave::~ChildProcessSlave() {}
void ChildProcessSlave::handleConnectionMade() {}
void ChildProcessSlave::handleConnectionLost() {}
bool ChildProcessSlave::sendMessageToMaster (const MemoryBlock& mb)
{
if (connection != nullptr)
return connection->sendMessage (mb);
jassertfalse; // this can only be used when the connection is active!
return false;
}
bool ChildProcessSlave::initialiseFromCommandLine (const String& commandLine,
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const String& commandLineUniqueID,
int timeoutMs)
{
String prefix (getCommandLinePrefix (commandLineUniqueID));
if (commandLine.trim().startsWith (prefix))
{
String pipeName (commandLine.fromFirstOccurrenceOf (prefix, false, false)
.upToFirstOccurrenceOf (" ", false, false).trim());
if (pipeName.isNotEmpty())
{
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connection = new Connection (*this, pipeName, timeoutMs <= 0 ? defaultTimeoutMs : timeoutMs);
if (! connection->isConnected())
connection = nullptr;
}
}
return connection != nullptr;
}