Merge remote-tracking branch 'upstream/master' into trustless-remote-builder-simple

1 files changed, 73 insertions, 40 deletions

diff --git a/src/libutil/serialise.cc b/src/libutil/serialise.cc
index 5c9f6f901..87c1099a1 100644
--- a/src/libutil/serialise.cc
+++ b/src/libutil/serialise.cc
@@ -11,23 +11,23 @@
 namespace nix {
 
 
-void BufferedSink::operator () (const unsigned char * data, size_t len)
+void BufferedSink::operator () (std::string_view data)
 {
-    if (!buffer) buffer = decltype(buffer)(new unsigned char[bufSize]);
+    if (!buffer) buffer = decltype(buffer)(new char[bufSize]);
 
-    while (len) {
+    while (!data.empty()) {
         /* Optimisation: bypass the buffer if the data exceeds the
            buffer size. */
-        if (bufPos + len >= bufSize) {
+        if (bufPos + data.size() >= bufSize) {
             flush();
-            write(data, len);
+            write(data);
             break;
         }
         /* Otherwise, copy the bytes to the buffer.  Flush the buffer
            when it's full. */
-        size_t n = bufPos + len > bufSize ? bufSize - bufPos : len;
-        memcpy(buffer.get() + bufPos, data, n);
-        data += n; bufPos += n; len -= n;
+        size_t n = bufPos + data.size() > bufSize ? bufSize - bufPos : data.size();
+        memcpy(buffer.get() + bufPos, data.data(), n);
+        data.remove_prefix(n); bufPos += n;
         if (bufPos == bufSize) flush();
     }
 }
@@ -38,7 +38,7 @@ void BufferedSink::flush()
     if (bufPos == 0) return;
     size_t n = bufPos;
     bufPos = 0; // don't trigger the assert() in ~BufferedSink()
-    write(buffer.get(), n);
+    write({buffer.get(), n});
 }
 
 
@@ -59,9 +59,9 @@ static void warnLargeDump()
 }
 
 
-void FdSink::write(const unsigned char * data, size_t len)
+void FdSink::write(std::string_view data)
 {
-    written += len;
+    written += data.size();
     static bool warned = false;
     if (warn && !warned) {
         if (written > threshold) {
@@ -70,7 +70,7 @@ void FdSink::write(const unsigned char * data, size_t len)
         }
     }
     try {
-        writeFull(fd, data, len);
+        writeFull(fd, data);
     } catch (SysError & e) {
         _good = false;
         throw;
@@ -84,7 +84,7 @@ bool FdSink::good()
 }
 
 
-void Source::operator () (unsigned char * data, size_t len)
+void Source::operator () (char * data, size_t len)
 {
     while (len) {
         size_t n = read(data, len);
@@ -96,12 +96,12 @@ void Source::operator () (unsigned char * data, size_t len)
 void Source::drainInto(Sink & sink)
 {
     std::string s;
-    std::vector<unsigned char> buf(8192);
+    std::vector<char> buf(8192);
     while (true) {
         size_t n;
         try {
             n = read(buf.data(), buf.size());
-            sink(buf.data(), n);
+            sink({buf.data(), n});
         } catch (EndOfFile &) {
             break;
         }
@@ -117,9 +117,9 @@ std::string Source::drain()
 }
 
 
-size_t BufferedSource::read(unsigned char * data, size_t len)
+size_t BufferedSource::read(char * data, size_t len)
 {
-    if (!buffer) buffer = decltype(buffer)(new unsigned char[bufSize]);
+    if (!buffer) buffer = decltype(buffer)(new char[bufSize]);
 
     if (!bufPosIn) bufPosIn = readUnbuffered(buffer.get(), bufSize);
 
@@ -138,12 +138,12 @@ bool BufferedSource::hasData()
 }
 
 
-size_t FdSource::readUnbuffered(unsigned char * data, size_t len)
+size_t FdSource::readUnbuffered(char * data, size_t len)
 {
     ssize_t n;
     do {
         checkInterrupt();
-        n = ::read(fd, (char *) data, len);
+        n = ::read(fd, data, len);
     } while (n == -1 && errno == EINTR);
     if (n == -1) { _good = false; throw SysError("reading from file"); }
     if (n == 0) { _good = false; throw EndOfFile("unexpected end-of-file"); }
@@ -158,10 +158,10 @@ bool FdSource::good()
 }
 
 
-size_t StringSource::read(unsigned char * data, size_t len)
+size_t StringSource::read(char * data, size_t len)
 {
     if (pos == s.size()) throw EndOfFile("end of string reached");
-    size_t n = s.copy((char *) data, len, pos);
+    size_t n = s.copy(data, len, pos);
     pos += n;
     return n;
 }
@@ -171,6 +171,39 @@ size_t StringSource::read(unsigned char * data, size_t len)
 #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::unique_ptr<Source> sinkToSource(
     std::function<void(Sink &)> fun,
     std::function<void()> eof)
@@ -192,13 +225,13 @@ std::unique_ptr<Source> sinkToSource(
         std::string cur;
         size_t pos = 0;
 
-        size_t read(unsigned char * data, size_t len) override
+        size_t read(char * data, size_t len) override
         {
             if (!coro)
-                coro = coro_t::pull_type([&](coro_t::push_type & yield) {
-                    LambdaSink sink([&](const unsigned char * data, size_t len) {
-                            if (len) yield(std::string((const char *) data, len));
-                        });
+                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);
                 });
 
@@ -211,7 +244,7 @@ std::unique_ptr<Source> sinkToSource(
             }
 
             auto n = std::min(cur.size() - pos, len);
-            memcpy(data, (unsigned char *) cur.data() + pos, n);
+            memcpy(data, cur.data() + pos, n);
             pos += n;
 
             return n;
@@ -225,24 +258,24 @@ std::unique_ptr<Source> sinkToSource(
 void writePadding(size_t len, Sink & sink)
 {
     if (len % 8) {
-        unsigned char zero[8];
+        char zero[8];
         memset(zero, 0, sizeof(zero));
-        sink(zero, 8 - (len % 8));
+        sink({zero, 8 - (len % 8)});
     }
 }
 
 
-void writeString(const unsigned char * buf, size_t len, Sink & sink)
+void writeString(std::string_view data, Sink & sink)
 {
-    sink << len;
-    sink(buf, len);
-    writePadding(len, sink);
+    sink << data.size();
+    sink(data);
+    writePadding(data.size(), sink);
 }
 
 
 Sink & operator << (Sink & sink, const string & s)
 {
-    writeString((const unsigned char *) s.data(), s.size(), sink);
+    writeString(s, sink);
     return sink;
 }
 
@@ -288,7 +321,7 @@ Sink & operator << (Sink & sink, const Error & ex)
 void readPadding(size_t len, Source & source)
 {
     if (len % 8) {
-        unsigned char zero[8];
+        char zero[8];
         size_t n = 8 - (len % 8);
         source(zero, n);
         for (unsigned int i = 0; i < n; i++)
@@ -297,7 +330,7 @@ void readPadding(size_t len, Source & source)
 }
 
 
-size_t readString(unsigned char * buf, size_t max, Source & source)
+size_t readString(char * buf, size_t max, Source & source)
 {
     auto len = readNum<size_t>(source);
     if (len > max) throw SerialisationError("string is too long");
@@ -312,7 +345,7 @@ string readString(Source & source, size_t max)
     auto len = readNum<size_t>(source);
     if (len > max) throw SerialisationError("string is too long");
     std::string res(len, 0);
-    source((unsigned char*) res.data(), len);
+    source(res.data(), len);
     readPadding(len, source);
     return res;
 }
@@ -361,17 +394,17 @@ Error readError(Source & source)
 }
 
 
-void StringSink::operator () (const unsigned char * data, size_t len)
+void StringSink::operator () (std::string_view data)
 {
     static bool warned = false;
     if (!warned && s->size() > threshold) {
         warnLargeDump();
         warned = true;
     }
-    s->append((const char *) data, len);
+    s->append(data);
 }
 
-size_t ChainSource::read(unsigned char * data, size_t len)
+size_t ChainSource::read(char * data, size_t len)
 {
     if (useSecond) {
         return source2.read(data, len);