Utility: move STL-specific stuff to DebugStl.h.

There's still <iosfwd> and <utility> lurking around, but even with that
the amount of preprocessed lines goes down from 14k to 3k under C++11
and from 17k to 4k under C++17. Nice.

I had to use the IsStringLike type trait to avoid forward-declaring /
including std::string and due to that there's a new operator<< for
std::basic_string of types other than char, since those would be now
interpreted as string-like. For now I'm keeping the current behavior of
printing only std::string as a string and all other (e.g.
std::u32string) as containers, but maybe it might make sense to revisit
this in the future and print all those types as strings.

doc/corrade-changelog.dox

@@ -154,6 +154,14 @@ namespace Corrade {
     from looking like it works on directories only, but such name then caused
     people to ask if it works on directories as well, not helping anything.
 
+@subsection corrade-changelog-latest-compatibility Potential compatibility breakages, removed APIs
+
+-   Support for @ref std::tuple and @ref std::string in
+    @ref Utility::Debug is now provided through a separate header,
+    @ref Corrade/Utility/DebugStl.h, to speed up compile times. Since including
+    it for backwards compatibility would practically revert the optimization,
+    you have to @cpp #include @ce it explicitly where needed.
+
 @subsection corrade-changelog-latest-documentation Documentation
 
 -   Updated docs of the @ref Corrade/Utility/Macros.h header mentioning what

src/Corrade/Containers/EnumSet.hpp

@@ -29,6 +29,8 @@
  * @brief Function @ref Corrade::Containers::enumSetDebugOutput()
  */
 
+#include <initializer_list>
+
 #include "Corrade/Containers/EnumSet.h"
 #include "Corrade/Utility/Debug.h"
 

src/Corrade/PluginManager/AbstractManager.cpp

@@ -35,7 +35,7 @@
 #include "Corrade/PluginManager/AbstractPlugin.h"
 #include "Corrade/PluginManager/PluginMetadata.h"
 #include "Corrade/Utility/Assert.h"
-#include "Corrade/Utility/Debug.h"
+#include "Corrade/Utility/DebugStl.h"
 #include "Corrade/Utility/Configuration.h"
 #include "Corrade/Utility/String.h"
 

src/Corrade/TestSuite/Compare/File.cpp

@@ -31,7 +31,7 @@
 #include <algorithm> /* std::max() */
 #endif
 
-#include "Corrade/Utility/Debug.h"
+#include "Corrade/Utility/DebugStl.h"
 #include "Corrade/Utility/Directory.h"
 
 namespace Corrade { namespace TestSuite {

src/Corrade/TestSuite/Compare/FileToString.cpp

@@ -30,7 +30,7 @@
 #include <algorithm> /* std::max() */
 #endif
 
-#include "Corrade/Utility/Debug.h"
+#include "Corrade/Utility/DebugStl.h"
 #include "Corrade/Utility/Directory.h"
 
 namespace Corrade { namespace TestSuite {

src/Corrade/TestSuite/Compare/StringToFile.cpp

@@ -30,7 +30,7 @@
 #include <algorithm> /* std::max() */
 #endif
 
-#include "Corrade/Utility/Debug.h"
+#include "Corrade/Utility/DebugStl.h"
 #include "Corrade/Utility/Directory.h"
 
 namespace Corrade { namespace TestSuite {

src/Corrade/TestSuite/Tester.h

@@ -39,6 +39,7 @@
 #include "Corrade/TestSuite/Compare/FloatingPoint.h"
 #include "Corrade/TestSuite/visibility.h"
 #include "Corrade/Utility/Debug.h"
+#include "Corrade/Utility/DebugStl.h" /** @todo remove once not needed */
 #include "Corrade/Utility/Macros.h"
 
 #ifdef CORRADE_TARGET_EMSCRIPTEN

src/Corrade/Utility/AbstractHash.h

@@ -32,6 +32,7 @@
 #include <string>
 
 #include "Corrade/Utility/Debug.h"
+#include "Corrade/Utility/DebugStl.h"
 
 namespace Corrade { namespace Utility {
 

src/Corrade/Utility/Arguments.cpp

@@ -34,7 +34,7 @@
 #include <sstream>
 
 #include "Corrade/Utility/Assert.h"
-#include "Corrade/Utility/Debug.h"
+#include "Corrade/Utility/DebugStl.h"
 #include "Corrade/Utility/String.h"
 
 /* For Arguments::environment() */

src/Corrade/Utility/CMakeLists.txt

@@ -49,6 +49,7 @@ if(WITH_UTILITY)
         ConfigurationGroup.h
         ConfigurationValue.h
         Debug.h
+        DebugStl.h
         Directory.h
         Endianness.h
         Format.h

src/Corrade/Utility/Configuration.cpp

@@ -32,7 +32,7 @@
 
 #include "Corrade/Containers/Array.h"
 #include "Corrade/Utility/Assert.h"
-#include "Corrade/Utility/Debug.h"
+#include "Corrade/Utility/DebugStl.h"
 #include "Corrade/Utility/Directory.h"
 #include "Corrade/Utility/String.h"
 

src/Corrade/Utility/Debug.cpp

@@ -53,6 +53,8 @@
 #endif
 #endif
 
+#include "Corrade/Utility/DebugStl.h"
+
 namespace Corrade { namespace Utility {
 
 namespace {
@@ -326,8 +328,6 @@ template<class T> Debug& Debug::print(const T& value) {
     return *this;
 }
 
-Debug& Debug::operator<<(const std::string& value) { return print(value); }
-
 Debug& Debug::operator<<(const void* const value) {
     std::ostringstream o;
     o << "0x" << std::hex << reinterpret_cast<std::uintptr_t>(value);
@@ -385,10 +385,6 @@ Debug& Debug::operator<<(std::nullptr_t) {
 }
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
-Debug& Debug::operator<<(Implementation::DebugOstreamFallback&& value) {
-    return print(value);
-}
-
 /* Doxygen can't match this to the declaration, eh. */
 Debug& operator<<(Debug& debug, Debug::Color value) {
     switch(value) {
@@ -411,6 +407,17 @@ Debug& operator<<(Debug& debug, Debug::Color value) {
 
     return debug << "Debug::Color(" << Debug::nospace << reinterpret_cast<void*>(static_cast<unsigned char>(char(value))) << Debug::nospace << ")";
 }
+
+/* For some reason Doxygen can't match this with the declaration in DebugStl.h */
+Debug& operator<<(Debug& debug, const std::string& value) {
+    return debug.print(value);
+}
+#endif
+
+#ifndef DOXYGEN_GENERATING_OUTPUT
+Debug& operator<<(Debug& debug, Implementation::DebugOstreamFallback&& value) {
+    return debug.print(value);
+}
 #endif
 
 }}

src/Corrade/Utility/Debug.h

@@ -27,12 +27,12 @@
 
 /** @file
  * @brief Class @ref Corrade::Utility::Debug, @ref Corrade::Utility::Warning, @ref Corrade::Utility::Error, @ref Corrade::Utility::Fatal
+ * @see @ref Corrade/Utility/DebugStl.h
  */
 
 #include <iosfwd>
-#include <string>
-#include <tuple>
 #include <type_traits>
+#include <utility> /** @todo consider putting this away as well (900 LOC) */
 
 #include "Corrade/Utility/Macros.h"
 #include "Corrade/Containers/EnumSet.h"
@@ -42,8 +42,6 @@
 
 namespace Corrade { namespace Utility {
 
-namespace Implementation { struct DebugOstreamFallback; }
-
 /**
 @brief Debug output handler
 
@@ -53,11 +51,20 @@ with newline character. Example usage:
 
 @snippet Utility.cpp Debug-usage
 
-Support for printing more types can be added by implementing function
-@ref operator<<(Debug&, const T&) for given type. If there is no
-@cpp operator<<() @ce implemented for printing given type using the @ref Debug
-class, suitable @ref std::ostream @cpp operator<<() @ce overload is used as
-fallback, if found.
+Support for printing more types can be added by implementing an overload of
+@ref operator<<(Debug&, const T&) for given type.
+
+@section Utility-Debug-stl Printing STL types
+
+To optimize compile times, the @ref Corrade/Utility/Debug.h header provides
+only support for printing builtin types, generic iterable containers and
+@ref std::pair. Printing of @ref std::string and @ref std::tuple is possible if
+you @cpp #include @ce a separate @ref Corrade/Utility/DebugStl.h header. This
+header also provides a fallback to @ref std::ostream @cpp operator<<() @ce
+overloads, if there's no @cpp operator<<() @ce implemented for printing given
+type using @ref Debug. Note that printing @ref std::vector or @ref std::map
+containers is already possible with the generic iterable container support in
+@ref Corrade/Utility/Debug.h.
 
 @section Utility-Debug-scoped-output Scoped output redirection
 
@@ -370,9 +377,9 @@ class CORRADE_UTILITY_EXPORT Debug {
          *
          * If there is already something in the output, puts a space before
          * the value, unless @ref nospace() was set immediately before.
-         * @see @ref operator<<(Debug&, const T&)
+         * @see @ref operator<<(Debug&, const std::string&),
+         *      @ref operator<<(Debug&, const T&)
          */
-        Debug& operator<<(const std::string& value);
         Debug& operator<<(const char* value);            /**< @overload */
         Debug& operator<<(const void* value);            /**< @overload */
         Debug& operator<<(bool value);                   /**< @overload */
@@ -430,9 +437,13 @@ class CORRADE_UTILITY_EXPORT Debug {
          */
         Debug& operator<<(std::nullptr_t);
 
-        #ifndef DOXYGEN_GENERATING_OUTPUT
-        Debug& operator<<(Implementation::DebugOstreamFallback&& value);
-        #endif
+    #ifdef DOXYGEN_GENERATING_OUTPUT
+    private:
+    #endif
+        /* Used by the out-of-class operator<<(Debug&, const std::string&) and
+           operator<<(Debug&, Implementation::DebugOstreamFallback&&) which is
+           defined in DebugStl.h. */
+        template<class T> CORRADE_UTILITY_LOCAL Debug& print(const T& value);
 
     #ifndef DOXYGEN_GENERATING_OUTPUT
     protected:
@@ -466,7 +477,6 @@ class CORRADE_UTILITY_EXPORT Debug {
         static CORRADE_UTILITY_LOCAL bool _globalColorBold;
         #endif
 
-        template<class T> CORRADE_UTILITY_LOCAL Debug& print(const T& value);
         CORRADE_UTILITY_LOCAL void resetColorInternal();
 
         std::ostream* _previousGlobalOutput;
@@ -493,23 +503,23 @@ template<class T> inline Debug& operator<<(Debug&& debug, const T& value) {
 #endif
 
 #ifdef DOXYGEN_GENERATING_OUTPUT
-/** @relates Debug
-@brief Operator for printing custom types to debug
+/** @relatesalso Debug
+@brief Operator for printing custom types to debug output
 @param debug     Debug class
 @param value     Value to be printed
 
 Support for printing custom types (i.e. those not handled by @ref std::iostream)
 can be added by implementing this function for given type.
 
-The function should convert the type to one of supported types (such as
-@ref std::string) and then call @ref Debug::operator<<(const std::string&) with
+The function should convert the type to one of supported types (such as the
+builtin types or @ref std::string) and then call @ref Debug::operator<<() with
 it. You can also use @ref Debug::nospace() and @ref Debug::newline().
  */
 template<class T> Debug& operator<<(Debug& debug, const T& value);
 #endif
 
-/** @relates Debug
-@brief Operator for printing iterable types to debug
+/** @relatesalso Debug
+@brief Operator for printing iterable types to debug output
 
 Prints the value as @cb{.shell-session} {a, b, c} @ce.
 */
@@ -518,7 +528,7 @@ template<class Iterable> Debug& operator<<(Debug& debug, const Iterable& value)
 #else
 /* libc++ from Apple's Clang "4.2" (3.2-svn) doesn't have constexpr operator
    bool for std::integral_constant, thus we need to use ::value instead */
-template<class Iterable> Debug& operator<<(typename std::enable_if<IsIterable<Iterable>::value && !std::is_same<Iterable, std::string>::value, Debug&>::type debug, const Iterable& value)
+template<class Iterable> Debug& operator<<(typename std::enable_if<IsIterable<Iterable>::value && !IsStringLike<Iterable>::value, Debug&>::type debug, const Iterable& value)
 #endif
 {
     debug << "{" << Debug::nospace;
@@ -544,39 +554,13 @@ namespace Implementation {
         typedef Sequence<sequence...> Type;
     };
     #endif
-
-    /* Used by operator<<(Debug&, std::tuple<>...) */
-    template<class T> inline void tupleDebugOutput(Debug&, const T&, Sequence<>) {}
-    template<class T, std::size_t i, std::size_t ...sequence> void tupleDebugOutput(Debug& debug, const T& tuple, Sequence<i, sequence...>) {
-        debug << std::get<i>(tuple);
-        #ifdef _MSC_VER
-        #pragma warning(push)
-        #pragma warning(disable:4127) /* conditional expression is constant (of course) */
-        #endif
-        if(i + 1 != std::tuple_size<T>::value)
-            debug << Debug::nospace << ",";
-        #ifdef _MSC_VER
-        #pragma warning(pop)
-        #endif
-        tupleDebugOutput(debug, tuple, Sequence<sequence...>{});
-    }
 }
 
-/** @relates Debug
-@brief Operator for printing tuple types to debug
+/** @relatesalso Debug
+@brief Print a @ref std::pair to debug output
 
-Prints the value as @cb{.shell-session} (first, second, third...) @ce.
+Prints the value as @cb{.shell-session} (first, second) @ce.
 */
-template<class ...Args> Debug& operator<<(Debug& debug, const std::tuple<Args...>& value) {
-    debug << "(" << Debug::nospace;
-    Implementation::tupleDebugOutput(debug, value, typename Implementation::GenerateSequence<sizeof...(Args)>::Type{});
-    debug << Debug::nospace << ")";
-    return debug;
-}
-
-/** @relates Debug
- * @overload
- */
 template<class T, class U> Debug& operator<<(Debug& debug, const std::pair<T, U>& value) {
     return debug << "(" << Debug::nospace << value.first << Debug::nospace << "," << value.second << Debug::nospace << ")";
 }
@@ -794,27 +778,6 @@ class CORRADE_UTILITY_EXPORT Fatal: public Error {
 /** @debugoperatorclassenum{Debug,Debug::Color} */
 CORRADE_UTILITY_EXPORT Debug& operator<<(Debug& debug, Debug::Color value);
 
-namespace Implementation {
-
-/* Used by Debug::operator<<(Implementation::DebugOstreamFallback&&) */
-struct DebugOstreamFallback {
-    template<class T> /*implicit*/ DebugOstreamFallback(const T& t): applier(&DebugOstreamFallback::applyImpl<T>), value(&t) {}
-
-    void apply(std::ostream& s) const {
-        (this->*applier)(s);
-    }
-
-    template<class T> void applyImpl(std::ostream& s) const {
-        s << *static_cast<const T*>(value);
-    }
-
-    using ApplierFunc = void(DebugOstreamFallback::*)(std::ostream&) const;
-    const ApplierFunc applier;
-    const void* value;
-};
-
-}
-
 }}
 
 #endif