From 1b1bd56777358ef2fa538a9b7b62c6e8c823489b Mon Sep 17 00:00:00 2001
From: johannst <johannes.stoelp@gmail.com>
Date: Sat, 26 Sep 2020 23:58:24 +0200
Subject: added finished flag to thread + catch exceptions in thread entry
 function as unwinding across entry fn would be catastrophic

---
 lib/executor.cc |  3 +++
 lib/thread.cc   | 16 +++++++++++++---
 lib/thread.h    |  3 +++
 3 files changed, 19 insertions(+), 3 deletions(-)

(limited to 'lib')

diff --git a/lib/executor.cc b/lib/executor.cc
index fb79b49..af49f0e 100644
--- a/lib/executor.cc
+++ b/lib/executor.cc
@@ -12,6 +12,9 @@ namespace nMatcha {
 
     void Executor::run() {
         for (const std::unique_ptr<Thread>& t : mThreads) {
+            if (t->isFinished()) {
+                continue;
+            }
             yield_to(t.get());
         }
     }
diff --git a/lib/thread.cc b/lib/thread.cc
index d665f49..ec7fd64 100644
--- a/lib/thread.cc
+++ b/lib/thread.cc
@@ -6,7 +6,9 @@
 #include "executor.h"
 
 #include <cassert>
-#include <cstdint>     // uintN_t
+#include <cstdint>  // uintN_t
+#include <exception>
+#include <iostream>
 #include <sys/mman.h>  // mmap
 #include <unistd.h>    // sysconf
 
@@ -15,7 +17,7 @@ namespace {
 }  // namespace
 
 namespace nMatcha {
-    Thread::Thread() : mStackPtr(nullptr), mExecutor(nullptr) {
+    Thread::Thread() : mStackPtr(nullptr), mFinished(false), mExecutor(nullptr) {
         const long PAGE_SIZE = get_pagesize();
         const long STACK_SIZE = 8 * PAGE_SIZE;
 
@@ -64,7 +66,15 @@ namespace nMatcha {
 
     void Thread::entry(void* obj) {
         Thread* t = static_cast<Thread*>(obj);
-        t->threadFn();
+        try {
+            t->threadFn();
+        } catch (const std::exception& e) {
+            std::cerr << "Thread: caught unhandled std::exception!\n" << e.what() << std::endl;
+        } catch (...) {
+            std::cerr << "Thread: caught unhandled unknown exception!" << std::endl;
+        }
+        t->mFinished = true;
+        t->yield();
     }
 
     void Thread::yield() {
diff --git a/lib/thread.h b/lib/thread.h
index e392052..d983734 100644
--- a/lib/thread.h
+++ b/lib/thread.h
@@ -13,12 +13,15 @@ namespace nMatcha {
 
         virtual void threadFn() = 0;
 
+        bool isFinished() const { return mFinished; }
+
       protected:
         void yield();
 
       private:
         static void entry(void* obj);
         void* mStackPtr;
+        bool mFinished;
 
         friend struct Executor;
         const Executor* mExecutor;
-- 
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