From 3df6609ac522b5eb7ab906198f59fe14c8bfc0da Mon Sep 17 00:00:00 2001
From: Oliver Kowalke <oliver.kowalke@gmail.com>
Date: Sat, 27 Jul 2019 14:12:00 +0200
Subject: [PATCH] examples regarding to unwinding

---
 example/Jamfile.v2         | 20 ++++++++++
 example/unwind_default.cpp | 63 ++++++++++++++++++++++++++++++
 example/unwind_return1.cpp | 73 +++++++++++++++++++++++++++++++++++
 example/unwind_return2.cpp | 71 ++++++++++++++++++++++++++++++++++
 example/unwind_throw1.cpp  | 75 ++++++++++++++++++++++++++++++++++++
 example/unwind_throw2.cpp  | 79 ++++++++++++++++++++++++++++++++++++++
 6 files changed, 381 insertions(+)
 create mode 100644 example/unwind_default.cpp
 create mode 100644 example/unwind_return1.cpp
 create mode 100644 example/unwind_return2.cpp
 create mode 100644 example/unwind_throw1.cpp
 create mode 100644 example/unwind_throw2.cpp

diff --git a/example/Jamfile.v2 b/example/Jamfile.v2
index 7794597..5c4c44c 100644
--- a/example/Jamfile.v2
+++ b/example/Jamfile.v2
@@ -90,6 +90,26 @@ exe unwind_main
     : unwind_main.cpp
     ;
 
+exe unwind_return1
+    : unwind_return1.cpp
+    ;
+
+exe unwind_return2
+    : unwind_return2.cpp
+    ;
+
+exe unwind_throw1
+    : unwind_throw1.cpp
+    ;
+
+exe unwind_throw2
+    : unwind_throw2.cpp
+    ;
+
+exe unwind_default
+    : unwind_default.cpp
+    ;
+
 #exe backtrace
 #    : backtrace.cpp
 #    ;
diff --git a/example/unwind_default.cpp b/example/unwind_default.cpp
new file mode 100644
index 0000000..b47d256
--- /dev/null
+++ b/example/unwind_default.cpp
@@ -0,0 +1,63 @@
+
+//          Copyright Oliver Kowalke 2019.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+
+#include <boost/context/fiber_context.hpp>
+
+namespace ctx = boost::context;
+
+class fibonacci_generator {
+private:
+    ctx::fiber_context  fcallee;
+    uint64_t            a;
+
+    void run_(ctx::fiber_context && fcaller) {
+        a=0;
+        int b=1;
+        for(;;){
+            fcaller = std::move( fcaller).resume();
+            int next=a+b;
+            a=b;
+            b=next;
+        }
+    }
+
+public:
+    fibonacci_generator() :
+        fcallee{
+            [this](ctx::fiber_context && fcaller) -> ctx::fiber_context {
+                run_( std::move( fcaller) );
+                return {};
+        } } {
+    }
+
+    ~fibonacci_generator() {
+        if ( fcallee) {
+            std::move( fcallee).resume_with( ctx::unwind_fiber);
+        }
+    }
+
+    fibonacci_generator( fibonacci_generator const&) = delete;
+    fibonacci_generator & operator=( fibonacci_generator const&) = delete;
+
+    uint64_t operator()() {
+        fcallee = std::move( fcallee).resume();
+        return a;
+    }
+};
+
+int main() {
+    fibonacci_generator generator;
+    for ( int j = 0; j < 10; ++j) {
+        std::cout << generator() << " ";
+    }
+    std::cout << std::endl;
+    std::cout << "main: done" << std::endl;
+    return EXIT_SUCCESS;
+}
diff --git a/example/unwind_return1.cpp b/example/unwind_return1.cpp
new file mode 100644
index 0000000..b91b5bf
--- /dev/null
+++ b/example/unwind_return1.cpp
@@ -0,0 +1,73 @@
+
+//          Copyright Oliver Kowalke 2019.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+
+#include <boost/context/fiber_context.hpp>
+
+namespace ctx = boost::context;
+
+class fibonacci_generator {
+private:
+    bool                terminate{ false };
+    ctx::fiber_context  fcallee;
+    ctx::fiber_context  fexit;
+    uint64_t            a;
+
+    void run_(ctx::fiber_context && fcaller) {
+        a=0;
+        int b=1;
+        for(;;){
+            fcaller = std::move( fcaller).resume();
+            if ( terminate) {
+                return;
+            }
+            int next=a+b;
+            a=b;
+            b=next;
+        }
+    }
+
+public:
+    fibonacci_generator() :
+        fcallee{
+            [this](ctx::fiber_context && fcaller) -> ctx::fiber_context {
+                run_( std::move( fcaller) );
+                return std::move( fexit);
+        } } {
+    }
+
+    ~fibonacci_generator() {
+        if ( fcallee) {
+            std::move( fcallee).resume_with(
+                    [this](ctx::fiber_context && f) -> ctx::fiber_context {
+                        terminate = true;
+                        fexit = std::move( f);
+                        return {};
+                    });
+        }
+    }
+
+    fibonacci_generator( fibonacci_generator const&) = delete;
+    fibonacci_generator & operator=( fibonacci_generator const&) = delete;
+
+    uint64_t operator()() {
+        fcallee = std::move( fcallee).resume();
+        return a;
+    }
+};
+
+int main() {
+    fibonacci_generator generator;
+    for ( int j = 0; j < 10; ++j) {
+        std::cout << generator() << " ";
+    }
+    std::cout << std::endl;
+    std::cout << "main: done" << std::endl;
+    return EXIT_SUCCESS;
+}
diff --git a/example/unwind_return2.cpp b/example/unwind_return2.cpp
new file mode 100644
index 0000000..2f0765f
--- /dev/null
+++ b/example/unwind_return2.cpp
@@ -0,0 +1,71 @@
+
+//          Copyright Oliver Kowalke 2019.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+
+#include <boost/context/fiber_context.hpp>
+
+namespace ctx = boost::context;
+
+class fibonacci_generator {
+private:
+    ctx::fiber_context  fcallee;
+    ctx::fiber_context  fexit;
+    uint64_t            a;
+
+    void run_(ctx::fiber_context && fcaller) {
+        a=0;
+        int b=1;
+        for(;;){
+            fcaller = std::move( fcaller).resume();
+            if ( ! fcaller) {
+                return;
+            }
+            int next=a+b;
+            a=b;
+            b=next;
+        }
+    }
+
+public:
+    fibonacci_generator() :
+        fcallee{
+            [this](ctx::fiber_context && fcaller) -> ctx::fiber_context {
+                run_( std::move( fcaller) );
+                return std::move( fexit);
+        } } {
+    }
+
+    ~fibonacci_generator() {
+        if ( fcallee) {
+            std::move( fcallee).resume_with(
+                    [this](ctx::fiber_context && f) -> ctx::fiber_context {
+                        fexit = std::move( f);
+                        return {};
+                    });
+        }
+    }
+
+    fibonacci_generator( fibonacci_generator const&) = delete;
+    fibonacci_generator & operator=( fibonacci_generator const&) = delete;
+
+    uint64_t operator()() {
+        fcallee = std::move( fcallee).resume();
+        return a;
+    }
+};
+
+int main() {
+    fibonacci_generator generator;
+    for ( int j = 0; j < 10; ++j) {
+        std::cout << generator() << " ";
+    }
+    std::cout << std::endl;
+    std::cout << "main: done" << std::endl;
+    return EXIT_SUCCESS;
+}
diff --git a/example/unwind_throw1.cpp b/example/unwind_throw1.cpp
new file mode 100644
index 0000000..110b911
--- /dev/null
+++ b/example/unwind_throw1.cpp
@@ -0,0 +1,75 @@
+
+//          Copyright Oliver Kowalke 2019.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+
+#include <boost/context/fiber_context.hpp>
+
+namespace ctx = boost::context;
+
+class fibonacci_generator {
+private:
+    struct my_unwind_exception {
+    };
+
+    ctx::fiber_context  fcallee;
+    ctx::fiber_context  fexit;
+    uint64_t            a;
+
+    void run_(ctx::fiber_context && fcaller) {
+        a=0;
+        int b=1;
+        for(;;){
+            fcaller = std::move( fcaller).resume();
+            int next=a+b;
+            a=b;
+            b=next;
+        }
+    }
+
+public:
+    fibonacci_generator() :
+        fcallee{
+            [this](ctx::fiber_context && fcaller) -> ctx::fiber_context {
+                try {
+                    run_( std::move( fcaller) );
+                } catch ( my_unwind_exception const&) {
+                }
+                return std::move( fexit);
+        } } {
+    }
+
+    ~fibonacci_generator() {
+        if ( fcallee) {
+            std::move( fcallee).resume_with(
+                    [this](ctx::fiber_context && f) -> ctx::fiber_context {
+                        fexit = std::move( f);
+                        throw my_unwind_exception{};
+                        return {};
+                    });
+        }
+    }
+
+    fibonacci_generator( fibonacci_generator const&) = delete;
+    fibonacci_generator & operator=( fibonacci_generator const&) = delete;
+
+    uint64_t operator()() {
+        fcallee = std::move( fcallee).resume();
+        return a;
+    }
+};
+
+int main() {
+    fibonacci_generator generator;
+    for ( int j = 0; j < 10; ++j) {
+        std::cout << generator() << " ";
+    }
+    std::cout << std::endl;
+    std::cout << "main: done" << std::endl;
+    return EXIT_SUCCESS;
+}
diff --git a/example/unwind_throw2.cpp b/example/unwind_throw2.cpp
new file mode 100644
index 0000000..0af28d3
--- /dev/null
+++ b/example/unwind_throw2.cpp
@@ -0,0 +1,79 @@
+
+//          Copyright Oliver Kowalke 2019.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#include <cstdlib>
+#include <iostream>
+#include <memory>
+
+#include <boost/context/fiber_context.hpp>
+
+namespace ctx = boost::context;
+
+class fibonacci_generator {
+private:
+    struct my_unwind_exception {
+        ctx::fiber_context  fexit;
+
+        my_unwind_exception( ctx::fiber_context && f) :
+            fexit{ std::move( f) } {
+        }
+    };
+
+    ctx::fiber_context  fcallee;
+    uint64_t            a;
+
+    void run_(ctx::fiber_context && fcaller) {
+        a=0;
+        int b=1;
+        for(;;){
+            fcaller = std::move( fcaller).resume();
+            int next=a+b;
+            a=b;
+            b=next;
+        }
+    }
+
+public:
+    fibonacci_generator() :
+        fcallee{
+            [this](ctx::fiber_context && fcaller) -> ctx::fiber_context {
+                try {
+                    run_( std::move( fcaller) );
+                } catch ( my_unwind_exception & ex) {
+                    return std::move( ex.fexit);
+                }
+                return {};
+        } } {
+    }
+
+    ~fibonacci_generator() {
+        if ( fcallee) {
+            std::move( fcallee).resume_with(
+                    [this](ctx::fiber_context && f) -> ctx::fiber_context {
+                        throw my_unwind_exception{ std::move( f) };
+                        return {};
+                    });
+        }
+    }
+
+    fibonacci_generator( fibonacci_generator const&) = delete;
+    fibonacci_generator & operator=( fibonacci_generator const&) = delete;
+
+    uint64_t operator()() {
+        fcallee = std::move( fcallee).resume();
+        return a;
+    }
+};
+
+int main() {
+    fibonacci_generator generator;
+    for ( int j = 0; j < 10; ++j) {
+        std::cout << generator() << " ";
+    }
+    std::cout << std::endl;
+    std::cout << "main: done" << std::endl;
+    return EXIT_SUCCESS;
+}