buffers_cat fixes and coverage:

* Fix operator== for default constructed iterators
* More tests and code coverage

CHANGELOG.md

@@ -2,6 +2,7 @@ Version 200
 
 * Don't include OpenSSL for core snippets
 * Tidy up msvc-14 workaround in multi_buffer
+* buffers_cat fixes and coverage
 
 --------------------------------------------------------------------------------
 

include/boost/beast/core/detail/variant.hpp

@@ -18,7 +18,6 @@ namespace boost {
 namespace beast {
 namespace detail {
 
-
 // This simple variant gets the job done without
 // causing too much trouble with template depth:
 //

include/boost/beast/core/impl/buffers_cat.hpp

@@ -170,6 +170,7 @@ private:
         reference
         operator()(mp11::mp_size_t<0>)
         {
+            // Dereferencing a default-constructed iterator
             BOOST_THROW_EXCEPTION(std::logic_error{
                 "invalid iterator"});
         }
@@ -279,11 +280,11 @@ operator==(const_iterator const& other) const
         (bn_ == nullptr) ?
         (
             other.bn_ == nullptr ||
-            other.it_.index() == sizeof...(Bn)
+            other.it_.index() == sizeof...(Bn) + 1
         ):(
             (other.bn_ == nullptr) ?
             (
-                it_.index() == sizeof...(Bn)
+                it_.index() == sizeof...(Bn) + 1
             ): (
                 bn_ == other.bn_ &&
                 it_ == other.it_

test/beast/core/buffers_cat.cpp

@@ -215,6 +215,64 @@ public:
         decltype(bs)::const_iterator it;
         decltype(bs2)::const_iterator it2;
         BEAST_EXPECT(it == it2);
+
+        // decrement begin() should throw
+        try
+        {
+            --bs.begin();
+            fail();
+        }
+        catch(std::logic_error const&)
+        {
+            pass();
+        }
+        catch(...)
+        {
+            fail();
+        }
+    }
+
+
+    void
+    testDefaultIterators()
+    {
+        // default ctor is one past the end
+        char c[2];
+        auto bs = buffers_cat(
+            net::const_buffer(&c[0], 1),
+            net::const_buffer(&c[1], 1));
+        decltype(bs)::const_iterator it;
+        BEAST_EXPECT(bs.end() == it);
+        BEAST_EXPECT(it == bs.end());
+        decltype(bs)::const_iterator it2;
+        BEAST_EXPECT(it == it2);
+        BEAST_EXPECT(it2 == it);
+        it = bs.end();
+        it2 = bs.end();
+        BEAST_EXPECT(it == it2);
+        BEAST_EXPECT(it2 == it);
+        decltype(bs)::const_iterator it3(it2);
+        BEAST_EXPECT(it3 == it2);
+        it = bs.begin();
+        BEAST_EXPECT(it != it3);
+        it = it3;
+        BEAST_EXPECT(it == it3);
+
+        // dereferencing default iterator should throw
+        try
+        {
+            it = {};
+            *it;
+            fail();
+        }
+        catch(std::logic_error const&)
+        {
+            pass();
+        }
+        catch(...)
+        {
+            fail();
+        }
     }
 
     void
@@ -309,6 +367,7 @@ public:
 
         testBufferCat();
         testIterators();
+        testDefaultIterators();
         testGccWarning1();
         testGccWarning2();
         test_empty_buffer_sequences();

test/beast/core/buffers_prefix.cpp

@@ -125,40 +125,6 @@ public:
 #endif
     }
 
-    void testIterator()
-    {
-        using net::buffer_size;
-        using net::const_buffer;
-        char b[3];
-        std::array<const_buffer, 3> bs{{
-            const_buffer{&b[0], 1},
-            const_buffer{&b[1], 1},
-            const_buffer{&b[2], 1}}};
-        auto pb = buffers_prefix(2, bs);
-        BEAST_EXPECT(bsize1(pb) == 2);
-        BEAST_EXPECT(bsize2(pb) == 2);
-        BEAST_EXPECT(bsize3(pb) == 2);
-        BEAST_EXPECT(bsize4(pb) == 2);
-
-        // default ctor is one past the end
-        decltype(pb)::const_iterator it;
-        BEAST_EXPECT(pb.end() == it);
-        BEAST_EXPECT(it == pb.end());
-        decltype(pb)::const_iterator it2;
-        BEAST_EXPECT(it == it2);
-        BEAST_EXPECT(it2 == it);
-        it = pb.end();
-        it2 = pb.end();
-        BEAST_EXPECT(it == it2);
-        BEAST_EXPECT(it2 == it);
-        decltype(pb)::const_iterator it3(it2);
-        BEAST_EXPECT(it3 == it2);
-        it = pb.begin();
-        BEAST_EXPECT(it != it3);
-        it = it3;
-        BEAST_EXPECT(it == it3);
-    }
-
     void testInPlaceInit()
     {
         {
@@ -208,13 +174,56 @@ public:
         }
     }
 
+    void testIterators()
+    {
+        char b[3];
+        std::array<net::const_buffer, 3> bs{{
+            net::const_buffer{&b[0], 1},
+            net::const_buffer{&b[1], 1},
+            net::const_buffer{&b[2], 1}}};
+        auto pb = buffers_prefix(2, bs);
+        BEAST_EXPECT(bsize1(pb) == 2);
+        BEAST_EXPECT(bsize2(pb) == 2);
+        BEAST_EXPECT(bsize3(pb) == 2);
+        BEAST_EXPECT(bsize4(pb) == 2);
+    }
+
+    void
+    testDefaultIterators()
+    {
+        // default ctor is one past the end
+        char b[3];
+        std::array<net::const_buffer, 3> bs{{
+            net::const_buffer{&b[0], 1},
+            net::const_buffer{&b[1], 1},
+            net::const_buffer{&b[2], 1}}};
+        auto pb = buffers_prefix(2, bs);
+        decltype(pb)::const_iterator it;
+        BEAST_EXPECT(pb.end() == it);
+        BEAST_EXPECT(it == pb.end());
+        decltype(pb)::const_iterator it2;
+        BEAST_EXPECT(it == it2);
+        BEAST_EXPECT(it2 == it);
+        it = pb.end();
+        it2 = pb.end();
+        BEAST_EXPECT(it == it2);
+        BEAST_EXPECT(it2 == it);
+        decltype(pb)::const_iterator it3(it2);
+        BEAST_EXPECT(it3 == it2);
+        it = pb.begin();
+        BEAST_EXPECT(it != it3);
+        it = it3;
+        BEAST_EXPECT(it == it3);
+    }
+
     void run() override
     {
         testMatrix<net::const_buffer>();
         testMatrix<net::mutable_buffer>();
         testEmptyBuffers();
-        testIterator();
         testInPlaceInit();
+        testIterators();
+        testDefaultIterators();
     }
 };