From 8a9e518371df03b3f382e0fe869da83751fdda0b Mon Sep 17 00:00:00 2001
From: jsmall-nvidia <jsmall@nvidia.com>
Date: Wed, 10 Nov 2021 17:33:22 -0500
Subject: Interprocess communication via pipes (#2009)

* #include an absolute path didn't work - because paths were taken to always be relative.

* Use 'Process' to communicate with an command line tool.

* Remove slang-win-stream

* Tidy up windows ProcessUtil.

* First version of BufferedReadStream.

* Windows working IPC for steams.

* Test proxy count option.

* Split Process/ProcessUtil. Process is platform dependant. ProcessUtil are functions that are platform independent.

* First implementation of Unix Process interface.

* Unix process compiles on cygwin.

* Fix typo in unix process.

* Separate unix pipe stream error of invalid access, from pipe availability.

* Fix in standard line extraction.

* Make fd non blocking.

* Fix issues with Windows Process streams.

* Added UnixPipe.

* Some fixes around UnixPipeStream.

* Make a unix stream closed explicit.

* Hack to debug linux process/stream.

* Revert to old linux pipe handling.

* Pass executable path for unit tests.
Split out CommandLine into own source.

* Small improvements in process/command line.

* Check process behavior with crash.

* Make stderr and stdout unbuffered for crash testing.

* Only turn disable buffering in crash test.

* Disable crash test on CI.

* Fix crash on clang/linux.

* Enable crash test.
Remove _appendBuffer as can use StreamUtil functionality.
---
 source/core/slang-process-util.cpp | 78 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 source/core/slang-process-util.cpp

(limited to 'source/core/slang-process-util.cpp')

diff --git a/source/core/slang-process-util.cpp b/source/core/slang-process-util.cpp
new file mode 100644
index 000000000..b1466d150
--- /dev/null
+++ b/source/core/slang-process-util.cpp
@@ -0,0 +1,78 @@
+// slang-process-util.cpp
+
+#include "slang-process-util.h"
+
+#include "slang-string.h"
+#include "slang-string-escape-util.h"
+#include "slang-string-util.h"
+
+#include "../../slang-com-helper.h"
+
+namespace Slang {
+
+/* static */SlangResult ProcessUtil::execute(const CommandLine& commandLine, ExecuteResult& outExecuteResult)
+{
+    RefPtr<Process> process;
+    SLANG_RETURN_ON_FAIL(Process::create(commandLine, 0, process));
+    SLANG_RETURN_ON_FAIL(readUntilTermination(process, outExecuteResult));
+    return SLANG_OK;
+}
+
+static Index _getCount(List<Byte>* buf)
+{
+    return buf ? buf->getCount() : 0;
+}
+
+// We may want something more sophisticated here, if bytes is something other than ascii/utf8
+static String _getText(const ConstArrayView<Byte>& bytes)
+{
+    StringBuilder buf;
+    StringUtil::appendStandardLines(UnownedStringSlice((const char*)bytes.begin(), (const char*)bytes.end()), buf);
+    return buf.ProduceString();
+}
+
+/* static */SlangResult ProcessUtil::readUntilTermination(Process* process, ExecuteResult& outExecuteResult)
+{
+    List<Byte> stdOut;
+    List<Byte> stdError;
+
+    SLANG_RETURN_ON_FAIL(readUntilTermination(process, &stdOut, &stdError));
+
+    // Get the return code
+    outExecuteResult.resultCode = ExecuteResult::ResultCode(process->getReturnValue());
+
+    outExecuteResult.standardOutput = _getText(stdOut.getArrayView());
+    outExecuteResult.standardError = _getText(stdError.getArrayView());
+
+    return SLANG_OK;
+}
+
+/* static */SlangResult ProcessUtil::readUntilTermination(Process* process, List<Byte>* outStdOut, List<Byte>* outStdError)
+{
+    Stream* stdOutStream = process->getStream(Process::StreamType::StdOut);
+    Stream* stdErrorStream = process->getStream(Process::StreamType::ErrorOut);
+
+    while (!process->isTerminated())
+    {
+        const auto preCount = _getCount(outStdOut) + _getCount(outStdError);
+
+        SLANG_RETURN_ON_FAIL(StreamUtil::readOrDiscard(stdOutStream, 0, outStdOut));
+        SLANG_RETURN_ON_FAIL(StreamUtil::readOrDiscard(stdErrorStream, 0, outStdError));
+
+        const auto postCount = _getCount(outStdOut) + _getCount(outStdError);
+
+        // If nothing was read, we can yield
+        if (preCount == postCount)
+        {
+            Process::sleepCurrentThread(0);
+        }
+    }
+
+    // Read anything remaining
+    SLANG_RETURN_ON_FAIL(StreamUtil::readOrDiscardAll(stdOutStream, 0, outStdOut));
+    SLANG_RETURN_ON_FAIL(StreamUtil::readOrDiscardAll(stdErrorStream, 0, outStdError));
+
+    return SLANG_OK;
+}
+
+} // namespace Slang
-- 
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