AZ::IO::FileDescriptorCapturer Class Reference

#include <SystemFile.h>

Public Types
using	OutputRedirectVisitor = AZStd::function< void(AZStd::span< AZStd::byte >)>

Public Member Functions
	FileDescriptorCapturer (int sourceDescriptor)
void	Start (OutputRedirectVisitor redirectCallback, AZStd::chrono::milliseconds waitTimeout=AZStd::chrono::seconds(1), int pipeSize=DefaultPipeSize)
void	Stop ()
	Stops capture of file descriptor and reset it back to it's previous value.
int	WriteBypassingCapture (const void *data, unsigned int size)

Static Public Attributes
static constexpr int	DefaultPipeSize = (1 << 16)

Detailed Description

Utility class for capturing the output of file descriptor redirection using with RAII behavior. NOTE: This class creates a new thread when Start() is called to pump the read end of the pipe when it is filled with data. The thread is terminated in Stop Example:

printf("Test"); // prints to stdout AZ::IO::FileDescriptorCapturer redirectStdoutToFile(1); redirectStdoutToFile.Start(); printf("Test"); // capture stdout as part of pipe bool testWasOutput{}; auto StdoutVisitor [&testWasOutput](AZStd::span<const AZStd::byte> capturedBytes) { AZStd::string_view capturedString(reinterpret_cast<const char*>(capturedBytes.data()), captureBytes.size()); testWasOutput = capturedString.contains("Test"); }; redirectStdout.Stop(StdoutVisitor); // Invokes visitor 0 or more times with captured data EXPECT_TRUE(testWasOutput);

Member Typedef Documentation

OutputRedirectVisitor

using AZ::IO::FileDescriptorCapturer::OutputRedirectVisitor = AZStd::function<void(AZStd::span<AZStd::byte>)>

Redirects file descriptor to a visitor callback Internally a pipe is used to send output to the visitor

NOTE: This function will be called on a different thread than the one used to invoke Start() The caller is responsible for ensuring thread safety with the callback function

Member Function Documentation

Start()

void AZ::IO::FileDescriptorCapturer::Start	(	OutputRedirectVisitor	redirectCallback,
		AZStd::chrono::milliseconds	waitTimeout = AZStd::chrono::seconds(1),
		int	pipeSize = DefaultPipeSize
	)

Starts capture of file descriptor

Parameters

redirectCallback	callback to invoke when data is available for read
waitTimeout	Timeout to wait for the descriptor to be signaled with data default to 1 seconds NOTE: This is not a timeout of the capture operation, but determines how frequently a polling operation retries. Using AZStd::chrono::milliseconds::max() results in an infinite timeout
pipeSize	used internally for pipe used to send captured data to the redirect callback redirectCallback will not receieve more data than pipeSize in a single invocation

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The documentation for this class was generated from the following file:

• Code/Framework/AzCore/AzCore/IO/SystemFile.h