Merge branch 'json-view/21-images' into json-view/22-view-dump-fast

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/view/document_data.hpp

@@ -78,7 +78,7 @@ struct document_data
         std::size_t text_cap = 0;
         std::size_t bytes = 0; ///< memory held by edits
     };
-    std::unique_ptr<edit_state> edits{}; ///< created by the first edit // NOLINT(readability-redundant-member-init)
+    std::unique_ptr<edit_state> edits; ///< created by the first edit
 
     /// one allocation for the header and room for `nodes` nodes; large
     /// documents get a separate node array instead (so it can be trimmed)
@@ -104,7 +104,23 @@ struct document_data
         }
     };
 
-    document_data() = default;
+    /// user-provided so that the class-type members can be initialized in the
+    /// member initialization list (-Weffc++ asks for it, and old GCC rejects a
+    /// defaulted constructor whose exception specification differs from the
+    /// implicit one); they cannot take default member initializers, which old
+    /// Clang (3.4-3.6) rejects. The other members have default member
+    /// initializers. noexcept: create() constructs into raw memory and could not
+    /// release it if this threw (the std::string default constructors do not
+    /// allocate).
+    document_data() noexcept
+        : arena() // NOLINT(readability-redundant-member-init)
+        , owned() // NOLINT(readability-redundant-member-init)
+        , owned_image() // NOLINT(readability-redundant-member-init)
+        , indexes() // NOLINT(readability-redundant-member-init)
+        , index_slots() // NOLINT(readability-redundant-member-init)
+        , large_objects() // NOLINT(readability-redundant-member-init)
+        , edits() // NOLINT(readability-redundant-member-init)
+    {}
     document_data(const document_data&) = delete;
     document_data(document_data&&) = delete;
     document_data& operator=(const document_data&) = delete;
@@ -219,6 +235,13 @@ struct document_data
 template<bool Editable>
 struct navigation
 {
+    /// whether the walk follows edits (the template argument as a runtime
+    /// condition: `Editable && ...` is a constant condition for MSVC, C4127)
+    static NLOHMANN_VIEW_ALWAYS_INLINE bool editable() noexcept
+    {
+        return false;
+    }
+
     static NLOHMANN_VIEW_ALWAYS_INLINE const node* first(const document_data& /*d*/, const node* n) noexcept
     {
         return n + 1;
@@ -238,6 +261,11 @@ struct navigation
 template<>
 struct navigation<true>
 {
+    static NLOHMANN_VIEW_ALWAYS_INLINE bool editable() noexcept
+    {
+        return true;
+    }
+
     static NLOHMANN_VIEW_ALWAYS_INLINE const node* first(const document_data& d, const node* n) noexcept
     {
         return d.first_child_edited(n);

include/nlohmann/detail/view/lookup.hpp

@@ -92,7 +92,7 @@ template<bool Editable>
 const node* find_member(const document_data& d, const node* object, const char* key, std::size_t n) noexcept
 {
     using nav = navigation<Editable>;
-    if (NLOHMANN_VIEW_UNLIKELY(object->extra != 0) && (!Editable || (object->flags & node_flags::moved) == 0))
+    if (NLOHMANN_VIEW_UNLIKELY(object->extra != 0) && (!nav::editable() || (object->flags & node_flags::moved) == 0))
     {
         return find_indexed(d, object, key, n); // a large object (whose members have not been edited)
     }
@@ -134,7 +134,7 @@ template<typename SizeType, typename IntegerType>
 SizeType to_index(IntegerType idx) noexcept
 {
     const IntegerType zero = 0;
-    const auto result = static_cast<SizeType>(idx); // NOLINT(bugprone-signed-char-misuse,cert-str34-c): idx is an index, not a character
+    const auto result = static_cast<SizeType>(idx); // NOLINT(bugprone-signed-char-misuse,cert-str34-c): negative values are mapped below
     return (idx < zero || static_cast<IntegerType>(result) != idx) ? (std::numeric_limits<SizeType>::max)() : result;
 }
 
@@ -143,8 +143,9 @@ SizeType to_index(IntegerType idx) noexcept
 template<bool Editable>
 const node* element_at(const document_data& d, const node* array, std::size_t idx) noexcept
 {
-    const node* e = navigation<Editable>::first(d, array);
-    if (Editable && (array->flags & node_flags::moved) != 0 && d.edits->moved_cap[array->off] != 0)
+    using nav = navigation<Editable>;
+    const node* e = nav::first(d, array);
+    if (nav::editable() && (array->flags & node_flags::moved) != 0 && d.edits->moved_cap[array->off] != 0)
     {
         return e + idx; // a growable block: one link per element
     }

include/nlohmann/detail/view/macro_scope.hpp

@@ -28,7 +28,10 @@
 #elif defined(_MSC_VER)
     #define NLOHMANN_VIEW_LIKELY(x) (x)
     #define NLOHMANN_VIEW_UNLIKELY(x) (x)
-    #define NLOHMANN_VIEW_ALWAYS_INLINE __forceinline
+    // plain inline: __forceinline makes MSVC report C4714 (not inlined) for
+    // function templates it cannot inline, which is an error under /WX; the
+    // forced inlining is only a performance hint
+    #define NLOHMANN_VIEW_ALWAYS_INLINE inline
     #define NLOHMANN_VIEW_NOINLINE __declspec(noinline)
 #else
     #define NLOHMANN_VIEW_LIKELY(x) (x)