Platform: port EmscriptenApplication away from std::string.

Co-authored-by: Squareys <squareys@googlemail.com>

src/Magnum/Platform/EmscriptenApplication.cpp

@@ -51,6 +51,8 @@
 
 namespace Magnum { namespace Platform {
 
+using namespace Containers::Literals;
+
 namespace {
     typedef EmscriptenApplication::KeyEvent::Key Key;
 
@@ -181,7 +183,7 @@ namespace {
         return Key::Unknown;
     }
 
-    std::string canvasId() {
+    Containers::String canvasId() {
         #pragma GCC diagnostic push
         #pragma GCC diagnostic ignored "-Wgnu-zero-variadic-macro-arguments"
         /* Note: can't use let or const, as that breaks closure compiler:
@@ -195,9 +197,7 @@ namespace {
             return memory;
         }));
         #pragma GCC diagnostic pop
-        std::string str = id;
-        std::free(id);
-        return str;
+        return Containers::String{id, [](char* data, std::size_t) { std::free(data); }};
     }
 
     bool checkForDeprecatedEmscriptenTargetBehavior() {
@@ -243,18 +243,18 @@ EmscriptenApplication::EmscriptenApplication(const Arguments& arguments, NoCreat
 
     /* Save command-line arguments */
     if(args.value("log") == "verbose") _verboseLog = true;
-    const std::string dpiScaling = args.value("dpi-scaling");
+    const Containers::StringView dpiScaling = args.value<Containers::StringView>("dpi-scaling");
 
     /* Use physical DPI scaling */
-    if(dpiScaling == "default" || dpiScaling == "physical") {
+    if(dpiScaling == "default"_s || dpiScaling == "physical"_s) {
 
     /* Use explicit dpi scaling vector */
-    } else if(dpiScaling.find_first_of(" \t\n") != std::string::npos)
-        _commandLineDpiScaling = args.value<Vector2>("dpi-scaling");
+    } else if(dpiScaling.containsAny(" \t\n"_s))
+        _commandLineDpiScaling = args.value<Vector2>("dpi-scaling"_s);
 
     /* Use explicit dpi scaling scalar */
     else
-        _commandLineDpiScaling = Vector2{args.value<Float>("dpi-scaling")};
+        _commandLineDpiScaling = Vector2{args.value<Float>("dpi-scaling"_s)};
 }
 
 EmscriptenApplication::~EmscriptenApplication() {
@@ -318,7 +318,7 @@ bool EmscriptenApplication::tryCreate(const Configuration& configuration) {
         Debug{verbose} << "Platform::EmscriptenApplication::tryCreate(): using old Emscripten target behavior";
     }
 
-    _canvasTarget = (_deprecatedTargetBehavior ? "" : "#") + canvasId();
+    _canvasTarget = (_deprecatedTargetBehavior ? canvasId() : "#"_s + canvasId());
 
     /* Get CSS canvas size and cache it. This is used later to detect canvas
        resizes in emscripten_set_resize_callback() and fire viewport events,
@@ -408,7 +408,7 @@ bool EmscriptenApplication::tryCreate(const Configuration& configuration, const
 
     /* Get the canvas ID from Module.canvas, either set by EmscriptenApplication.js
        or overridden/manually set by the user. */
-    _canvasTarget = (_deprecatedTargetBehavior ? "" : "#") + canvasId();
+    _canvasTarget = (_deprecatedTargetBehavior ? canvasId() : "#"_s + canvasId());
 
     /* Get CSS canvas size and cache it. This is used later to detect canvas
        resizes in emscripten_set_resize_callback() and fire viewport events,
@@ -469,23 +469,27 @@ Vector2i EmscriptenApplication::framebufferSize() const {
 }
 #endif
 
-void EmscriptenApplication::setWindowTitle(const std::string& title) {
+void EmscriptenApplication::setWindowTitle(const Containers::StringView title) {
     #pragma GCC diagnostic push
     #pragma GCC diagnostic ignored "-Wdollar-in-identifier-extension"
-    EM_ASM_({document.title = UTF8ToString($0);}, title.data());
+    EM_ASM_({document.title = UTF8ToString($0, $1);}, title.data(), title.size());
     #pragma GCC diagnostic pop
 }
 
-void EmscriptenApplication::setContainerCssClass(const std::string& cssClass) {
+void EmscriptenApplication::setContainerCssClass(const Containers::StringView cssClass) {
     #pragma GCC diagnostic push
     #pragma GCC diagnostic ignored "-Wdollar-in-identifier-extension"
     EM_ASM_({
         /* Handle also the classic #container for backwards compatibility. We
            also need to preserve the mn-container otherwise next time we'd have
-           no way to look for it anymore. */
+           no way to look for it anymore.
+
+           Using UTF8ToString() instead of AsciiToString() as it has an
+           explicit size parameter and thus doesn't need a null-terminated
+           input, which would potentially require yet another allocation. */
         (Module['canvas'].closest('.mn-container') ||
-         document.getElementById('container')).className = (['mn-container', AsciiToString($0)]).join(' ');
-    }, cssClass.data());
+         document.getElementById('container')).className = (['mn-container', UTF8ToString($0, $1)]).join(' ');
+    }, cssClass.data(), cssClass.size());
     #pragma GCC diagnostic pop
 
     /* Trigger a potential viewport event -- we don't poll the canvas size like
@@ -605,17 +609,15 @@ void EmscriptenApplication::setupCallbacks(bool resizable) {
     }));
     #pragma GCC diagnostic pop
 
-    std::string keyboardListeningElementString;
+    Containers::String keyboardListeningElementStorage;
     if(keyboardListeningElement == EMSCRIPTEN_EVENT_TARGET_DOCUMENT) {
         keyboardListeningElement = _deprecatedTargetBehavior ? "#document" : keyboardListeningElement;
     } else if(keyboardListeningElement == EMSCRIPTEN_EVENT_TARGET_WINDOW) {
         keyboardListeningElement = _deprecatedTargetBehavior ? "#window" : keyboardListeningElement;
-    } else if(keyboardListeningElement) {
-        if(!_deprecatedTargetBehavior)
-            keyboardListeningElementString = "#";
-        keyboardListeningElementString += keyboardListeningElement;
+    } else if(keyboardListeningElement && !_deprecatedTargetBehavior) {
+        keyboardListeningElementStorage = "#"_s + Containers::StringView{keyboardListeningElement};
         std::free(const_cast<char*>(keyboardListeningElement));
-        keyboardListeningElement = keyboardListeningElementString.data();
+        keyboardListeningElement = keyboardListeningElementStorage.data();
     }
 
     /* Happens only if keyboardListeningElement was set, but did not have an
@@ -918,7 +920,7 @@ Key EmscriptenApplication::KeyEvent::key() const {
     return toKey(_event.key, _event.code);
 }
 
-std::string EmscriptenApplication::KeyEvent::keyName() const {
+Containers::StringView EmscriptenApplication::KeyEvent::keyName() const {
     if((_event.key[0] >= 'a' && _event.key[0] <= 'z') ||
        (_event.key[0] >= 'A' && _event.key[0] <= 'Z')) return _event.key;
 

src/Magnum/Platform/EmscriptenApplication.h

@@ -34,12 +34,11 @@
  */
 #endif
 
-#include <string>
 #include <Corrade/Containers/ArrayView.h>
-
 /* Needed by the MAGNUM_EMSCRIPTENAPPLICATION_MAIN() macro */
 /** @todo use an Optional */
 #include <Corrade/Containers/Pointer.h>
+#include <Corrade/Containers/String.h> /** @todo PIMPL Configuration instead? */
 
 #include "Magnum/Magnum.h"
 #include "Magnum/Tags.h"
@@ -52,6 +51,11 @@
 #include "Magnum/Platform/GLContext.h"
 #endif
 
+#ifdef MAGNUM_BUILD_DEPRECATED
+/* Some APIs used to take or return a std::string before */
+#include <Corrade/Containers/StringStl.h>
+#endif
+
 #if defined(CORRADE_TARGET_EMSCRIPTEN) || defined(DOXYGEN_GENERATING_OUTPUT)
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
@@ -521,7 +525,7 @@ class EmscriptenApplication {
          *
          * The @p title is expected to be encoded in UTF-8.
          */
-        void setWindowTitle(const std::string& title);
+        void setWindowTitle(Containers::StringView title);
 
         /**
          * @brief Set container CSS class
@@ -542,7 +546,7 @@ class EmscriptenApplication {
          *      @cb{.html} <div class="mn-container"> @ce is not found. This
          *      compatibility is scheduled to be removed in the future.
          */
-        void setContainerCssClass(const std::string& cssClass);
+        void setContainerCssClass(Containers::StringView cssClass);
 
         /**
          * @brief Swap buffers
@@ -906,7 +910,7 @@ class EmscriptenApplication {
         Cursor _cursor;
 
         bool _deprecatedTargetBehavior{};
-        std::string _canvasTarget;
+        Containers::String _canvasTarget;
 
         #ifdef MAGNUM_TARGET_GL
         EMSCRIPTEN_WEBGL_CONTEXT_HANDLE _glContext{};
@@ -1845,8 +1849,14 @@ class EmscriptenApplication::KeyEvent: public EmscriptenApplication::InputEvent
          */
         Key key() const;
 
-        /** @brief Key name */
-        std::string keyName() const;
+        /**
+         * @brief Key name
+         *
+         * The returned view is always
+         * @relativeref{Corrade,Containers::StringViewFlag::NullTerminated} and
+         * is valid until the event is destroyed.
+         */
+        Containers::StringView keyName() const;
 
         /** @brief Modifiers */
         Modifiers modifiers() const;

src/Magnum/Platform/Test/EmscriptenApplicationTest.cpp

@@ -36,6 +36,7 @@
 
 namespace Magnum { namespace Platform { namespace Test {
 
+using namespace Containers::Literals;
 using namespace Math::Literals;
 
 struct EmscriptenApplicationTest: Platform::Application {
@@ -108,10 +109,10 @@ struct EmscriptenApplicationTest: Platform::Application {
             stopTextInput();
         } else if(event.key() == KeyEvent::Key::F) {
             Debug{} << "toggling fullscreen";
-            setContainerCssClass((_fullscreen ^= true) ? "mn-fullsize" : "");
+            setContainerCssClass((_fullscreen ^= true) ? "mn-fullsizeX"_s.exceptSuffix(1) : "");
         } else if(event.key() == KeyEvent::Key::T) {
             Debug{} << "setting window title";
-            setWindowTitle("This is a UTF-8 Window Title™!");
+            setWindowTitle("This is a UTF-8 Window Title™ and it should have no exclamation mark!!"_s.exceptSuffix(2));
         } else if(event.key() == KeyEvent::Key::H) {
             Debug{} << "toggling hand cursor";
             setCursor(cursor() == Cursor::Arrow ? Cursor::Hand : Cursor::Arrow);