remove sourceToSink, sinkToSource, and boehm patch

Change-Id: I1379841299713175d0225b82a67f50660f9eb5e2

3 files changed, 0 insertions, 243 deletions

diff --git a/src/libexpr/eval.cc b/src/libexpr/eval.cc
index ced92136b..77b46c2ed 100644
--- a/src/libexpr/eval.cc
+++ b/src/libexpr/eval.cc
@@ -192,42 +192,6 @@ static void * oomHandler(size_t requested)
     throw std::bad_alloc();
 }
 
-class BoehmGCStackAllocator : public StackAllocator {
-    boost::coroutines2::protected_fixedsize_stack stack {
-        // We allocate 8 MB, the default max stack size on NixOS.
-        // A smaller stack might be quicker to allocate but reduces the stack
-        // depth available for source filter expressions etc.
-        std::max(boost::context::stack_traits::default_size(), static_cast<std::size_t>(8 * 1024 * 1024))
-    };
-
-    // This is specific to boost::coroutines2::protected_fixedsize_stack.
-    // The stack protection page is included in sctx.size, so we have to
-    // subtract one page size from the stack size.
-    std::size_t pfss_usable_stack_size(boost::context::stack_context &sctx) {
-        return sctx.size - boost::context::stack_traits::page_size();
-    }
-
-  public:
-    boost::context::stack_context allocate() override {
-        auto sctx = stack.allocate();
-
-        // Stacks generally start at a high address and grow to lower addresses.
-        // Architectures that do the opposite are rare; in fact so rare that
-        // boost_routine does not implement it.
-        // So we subtract the stack size.
-        GC_add_roots(static_cast<char *>(sctx.sp) - pfss_usable_stack_size(sctx), sctx.sp);
-        return sctx;
-    }
-
-    void deallocate(boost::context::stack_context sctx) override {
-        GC_remove_roots(static_cast<char *>(sctx.sp) - pfss_usable_stack_size(sctx), sctx.sp);
-        stack.deallocate(sctx);
-    }
-
-};
-
-static BoehmGCStackAllocator boehmGCStackAllocator;
-
 #endif
 
 
@@ -243,23 +207,6 @@ static Symbol getName(const AttrName & name, EvalState & state, Env & env)
     }
 }
 
-#if HAVE_BOEHMGC
-/* Disable GC while this object lives. Used by CoroutineContext.
- *
- * Boehm keeps a count of GC_disable() and GC_enable() calls,
- * and only enables GC when the count matches.
- */
-class BoehmDisableGC {
-public:
-    BoehmDisableGC() {
-        GC_disable();
-    };
-    ~BoehmDisableGC() {
-        GC_enable();
-    };
-};
-#endif
-
 static bool gcInitialised = false;
 
 void initGC()
@@ -281,17 +228,6 @@ void initGC()
 
     GC_set_oom_fn(oomHandler);
 
-    StackAllocator::defaultAllocator = &boehmGCStackAllocator;
-
-
-#if NIX_BOEHM_PATCH_VERSION != 1
-    printTalkative("Unpatched BoehmGC, disabling GC inside coroutines");
-    /* Used to disable GC when entering coroutines on macOS */
-    create_coro_gc_hook = []() -> std::shared_ptr<void> {
-        return std::make_shared<BoehmDisableGC>();
-    };
-#endif
-
     /* Set the initial heap size to something fairly big (25% of
        physical RAM, up to a maximum of 384 MiB) so that in most cases
        we don't need to garbage collect at all.  (Collection has a
diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 11bc183cc..a294a7ea1 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -149,177 +149,6 @@ size_t StringSource::read(char * data, size_t len)
 }
 
 
-#if BOOST_VERSION >= 106300 && BOOST_VERSION < 106600
-#error Coroutines are broken in this version of Boost!
-#endif
-
-/* A concrete datatype allow virtual dispatch of stack allocation methods. */
-struct VirtualStackAllocator {
-    StackAllocator *allocator = StackAllocator::defaultAllocator;
-
-    boost::context::stack_context allocate() {
-        return allocator->allocate();
-    }
-
-    void deallocate(boost::context::stack_context sctx) {
-        allocator->deallocate(sctx);
-    }
-};
-
-
-/* This class reifies the default boost coroutine stack allocation strategy with
-   a virtual interface. */
-class DefaultStackAllocator : public StackAllocator {
-    boost::coroutines2::default_stack stack;
-
-    boost::context::stack_context allocate() {
-        return stack.allocate();
-    }
-
-    void deallocate(boost::context::stack_context sctx) {
-        stack.deallocate(sctx);
-    }
-};
-
-static DefaultStackAllocator defaultAllocatorSingleton;
-
-StackAllocator *StackAllocator::defaultAllocator = &defaultAllocatorSingleton;
-
-
-std::shared_ptr<void> (*create_coro_gc_hook)() = []() -> std::shared_ptr<void> {
-    return {};
-};
-
-/* This class is used for entry and exit hooks on coroutines */
-class CoroutineContext {
-    /* Disable GC when entering the coroutine without the boehm patch,
-     * since it doesn't find the main thread stack in this case.
-     * std::shared_ptr<void> performs type-erasure, so it will call the right
-     * deleter. */
-    const std::shared_ptr<void> coro_gc_hook = create_coro_gc_hook();
-public:
-    CoroutineContext() {};
-    ~CoroutineContext() {};
-};
-
-std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun)
-{
-    struct SourceToSink : FinishSink
-    {
-        typedef boost::coroutines2::coroutine<bool> coro_t;
-
-        std::function<void(Source &)> fun;
-        std::optional<coro_t::push_type> coro;
-
-        SourceToSink(std::function<void(Source &)> fun) : fun(fun)
-        {
-        }
-
-        std::string_view cur;
-
-        void operator () (std::string_view in) override
-        {
-            if (in.empty()) return;
-            cur = in;
-
-            if (!coro) {
-                CoroutineContext ctx;
-                coro = coro_t::push_type(VirtualStackAllocator{}, [&](coro_t::pull_type & yield) {
-                    LambdaSource source([&](char *out, size_t out_len) {
-                        if (cur.empty()) {
-                            yield();
-                            if (yield.get()) {
-                                throw EndOfFile("coroutine exhausted");
-                            }
-                        }
-
-                        size_t n = std::min(cur.size(), out_len);
-                        memcpy(out, cur.data(), n);
-                        cur.remove_prefix(n);
-                        return n;
-                    });
-                    fun(source);
-                });
-            }
-
-            if (!*coro) { abort(); }
-
-            if (!cur.empty()) {
-                CoroutineContext ctx;
-                (*coro)(false);
-            }
-        }
-
-        void finish() override
-        {
-            if (!coro) return;
-            if (!*coro) abort();
-            {
-                CoroutineContext ctx;
-                (*coro)(true);
-            }
-            if (*coro) abort();
-        }
-    };
-
-    return std::make_unique<SourceToSink>(fun);
-}
-
-
-std::unique_ptr<Source> sinkToSource(std::function<void(Sink &)> fun)
-{
-    struct SinkToSource : Source
-    {
-        typedef boost::coroutines2::coroutine<std::string> coro_t;
-
-        std::function<void(Sink &)> fun;
-        std::optional<coro_t::pull_type> coro;
-
-        SinkToSource(std::function<void(Sink &)> fun)
-            : fun(fun)
-        {
-        }
-
-        std::string cur;
-        size_t pos = 0;
-
-        size_t read(char * data, size_t len) override
-        {
-            if (!coro) {
-                CoroutineContext ctx;
-                coro = coro_t::pull_type(VirtualStackAllocator{}, [&](coro_t::push_type & yield) {
-                    LambdaSink sink([&](std::string_view data) {
-                        if (!data.empty()) yield(std::string(data));
-                    });
-                    fun(sink);
-                });
-            }
-
-            if (!*coro) {
-                throw EndOfFile("coroutine has finished");
-            }
-
-            if (pos == cur.size()) {
-                if (!cur.empty()) {
-                    CoroutineContext ctx;
-                    (*coro)();
-                }
-                cur = coro->get();
-                pos = 0;
-            }
-
-            auto n = std::min(cur.size() - pos, len);
-            memcpy(data, cur.data() + pos, n);
-            pos += n;
-
-            return n;
-        }
-    };
-
-    return std::make_unique<SinkToSource>(fun);
-}
-
-
 void writePadding(size_t len, Sink & sink)
 {
     if (len % 8) {
diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh
index 874c67b75..9b1892bbb 100644
--- a/src/libutil/serialise.hh
+++ b/src/libutil/serialise.hh
@@ -362,14 +362,6 @@ private:
     Bytes buf{};
 };
 
-std::unique_ptr<FinishSink> sourceToSink(std::function<void(Source &)> fun);
-
-/**
- * Convert a function that feeds data into a Sink into a Source. The
- * Source executes the function as a coroutine.
- */
-std::unique_ptr<Source> sinkToSource(std::function<void(Sink &)> fun);
-
 inline Sink & operator<<(Sink & sink, Generator<Bytes> && g)
 {
     while (auto buffer = g.next()) {