From ace4e334bc5fb299d2890b5e3f35dfd84ea32606 Mon Sep 17 00:00:00 2001
From: jsmall-nvidia <jsmall@nvidia.com>
Date: Tue, 30 Nov 2021 16:34:52 -0500
Subject: Use test-server on CI (#2034)

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

* Vary what SpawnType is used, if one isn't explicitly set.

* Terminate on linux if exec fails.

* Use a more sophisticated sleeping mechanism.

* Attempt to make CI tests to work on aarch64 debug.
Small fixes.
---
 source/core/slang-http.cpp              | 49 +++++++++++++++++++++++++++++++--
 source/core/unix/slang-unix-process.cpp | 16 +++++++++++
 2 files changed, 63 insertions(+), 2 deletions(-)

(limited to 'source/core')

diff --git a/source/core/slang-http.cpp b/source/core/slang-http.cpp
index 6a4bb4f92..bb5994635 100644
--- a/source/core/slang-http.cpp
+++ b/source/core/slang-http.cpp
@@ -287,6 +287,46 @@ SlangResult HTTPPacketConnection::update()
     return m_readResult;
 }
 
+
+namespace { // anonymous
+
+// Handles binary backoff like sleeping mechanism.
+struct SleepState
+{
+    void sleep()
+    {
+        Process::sleepCurrentThread(m_intervalInMs);
+        _update();
+    }
+    void reset()
+    {
+        m_intervalInMs = 0;
+        m_count = 0;
+    }
+    void _update()
+    {
+        const Int maxIntervalInMs = 32;
+        const Int initialCountThreshold = 4;
+
+        ++m_count;
+
+        const Int countThreshold = (m_intervalInMs == 0) ? initialCountThreshold : 1;
+
+        // If we hit the count change the interval
+        if (m_count >= countThreshold)
+        {
+            m_intervalInMs = (m_intervalInMs == 0) ? 1 : Math::Min(m_intervalInMs * 2, maxIntervalInMs);
+            // Reset the count
+            m_count = 0;
+        }
+    }
+
+    Int m_intervalInMs = 0;
+    Int m_count = 0;
+};
+
+} // anonymous
+
 SlangResult HTTPPacketConnection::waitForResult(Int timeOutInMs)
 {
     m_readResult = SLANG_OK;
@@ -300,6 +340,8 @@ SlangResult HTTPPacketConnection::waitForResult(Int timeOutInMs)
         startTick = Process::getClockTick();
     }
 
+    SleepState sleepState;
+
     while (m_readState == ReadState::Header ||
         m_readState == ReadState::Content)
     {
@@ -320,8 +362,11 @@ SlangResult HTTPPacketConnection::waitForResult(Int timeOutInMs)
 
         if (prevCount == m_readStream->getCount())
         {
-            // Yield if it appears nothing was read.
-            Process::sleepCurrentThread(0);
+            sleepState.sleep();
+        }
+        else
+        {
+            sleepState.reset();
         }
     }
 
diff --git a/source/core/unix/slang-unix-process.cpp b/source/core/unix/slang-unix-process.cpp
index 5131e37ec..4e8344486 100644
--- a/source/core/unix/slang-unix-process.cpp
+++ b/source/core/unix/slang-unix-process.cpp
@@ -349,6 +349,8 @@ SlangResult UnixPipeStream::write(const void* buffer, size_t length)
     return StringEscapeUtil::getHandler(StringEscapeUtil::Style::Space);
 }
 
+static const int kCannotExecute = 126;
+
 /* static */SlangResult Process::create(const CommandLine& commandLine, Process::Flags flags, RefPtr<Process>& outProcess)
 {
     List<char const*> argPtrs;
@@ -376,6 +378,12 @@ SlangResult UnixPipeStream::write(const void* buffer, size_t length)
         return SLANG_FAIL;
     }
 
+    // TODO(JS): 
+    // Ideally we'd have a mechanism to test if execvp can be successfully executed (at least in principal) before
+    // doing fork. Once we have forked we then have the problem of communicating to the parent process somehow.
+    //
+    // We could do a search down PATH and test files etc, but this seems to repeat a lot of the functionality of exec.
+    //    
     pid_t childPid = fork();
     if (childPid == -1)
     {
@@ -402,6 +410,11 @@ SlangResult UnixPipeStream::write(const void* buffer, size_t length)
         ::close(stdinPipe[0]);
         ::close(stdinPipe[1]);
 
+        // TODO(JS): Strictly speaking if m_executableType is 'Path' then we shouldn't be searching. Ie which
+        // exec we use here should be dependent on the executable type.
+
+        // Path = execvp
+        // Filename = execv
         ::execvp(argPtrs[0], (char* const*)&argPtrs[0]);
 
         // If we get here, then `exec` failed
@@ -410,6 +423,9 @@ SlangResult UnixPipeStream::write(const void* buffer, size_t length)
         // the terminal but in the stderrPipe. 
         fprintf(stderr, "error: `exec` failed\n");
 
+        // Terminate with failure. 
+        exit(kCannotExecute);
+
         return SLANG_FAIL;
     }
     else
-- 
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