Optimize string (mis)handling (#8128)

* Optimize statbar drawing

The texture name of the statbar is a string passed by value.
That slows down the client and creates litter in the heap
as the content of the string is allocated there. Convert the
offending parameter to a const reference to avoid the
performance hit.

* Optimize texture cache

There is an unnecessary temporary created when the texture
path is being generated. This slows down the cache each time
a new texture is encountered and it needs to be loaded into
the cache. Additionally, the heap litter created by this
unnecessary temporary is particularly troublesome here as
the following code then piles another string (the resulting
full path of the texture) on top of it, followed by the
texture itself, which both are quite long term objects as
they are subsequently inserted into the cache where they can
remain for quite a while (especially if the texture turns
out to be a common one like dirt, grass or stone).

Use std::string.append to get rid of the temporary which
solves both issues (speed and heap fragmentation).

* Optimize animations in client

Each time an animated node is updated, an unnecessary copy of
the texture name is created, littering the heap with lots of
fragments. This can be specifically troublesome when looking
at oceans or large lava lakes as both of these nodes are
usually animated (the lava animation is pretty visible).
Convert the parameter of GenericCAO::updateTextures to a
const reference to get rid of the unnecessary copy.

There is a comment stating "std::string copy is mandatory as
mod can be a class member and there is a swap on those class
members ... do NOT pass by reference", reinforcing the
belief that the unnecessary copy is in fact necessary.
However one of the first things the code of the method does
is to assign the parameter to its class member, creating
another copy. By rearranging the code a little bit this
"another copy" can then be used by the subsequent code,
getting rid of the need to pass the parameter by value and
thus saving that copying effort.

* Optimize chat console history handling

The GUIChatConsole::replaceAndAddToHistory was getting the
line to work on by value which turns out to be unnecessary.
Get rid of that unnecessary copy by converting the parameter
to a const reference.

* Optimize gui texture setting

The code used to set the texture for GUI components was
getting the name of the texture by value, creating
unnecessary performance bottleneck for mods/games with
heavily textured GUIs. Get rid of the bottleneck by passing
the texture name as a const reference.

* Optimize sound playing code in GUIEngine

The GUIEngine's code receives the specification of the sound
to be played by value, which turns out to be most likely a
mistake as the underlying sound manager interface receives
the same thing by reference. Convert the offending parameter
to a const reference to get rid of the rather bulky copying
effort and the associated performance hit.

* Silence CLANG TIDY warnings for unit tests

Change "std::string" to "const std::string &" to avoid an
unnecessary local value copy, silencing the CLANG TIDY
process.

* Optimize formspec handling

The "formspec prepend" parameter was passed to the formspec
handling code by value, creating unnecessary copy of
std::string and slowing down the game if mods add things like
textured backgrounds for the player inventory and/or other
forms. Get rid of that performance bottleneck by converting
the parameter to a const reference.

* Optimize hotbar image handling

The code that sets the background images for the hotbar is
getting the name of the image by value, creating an
unnecessary std::string copying effort. Fix that by
converting the relevant parameters to const references.

* Optimize inventory deserialization

The inventory manager deserialization code gets the
serialized version of the inventory by value, slowing the
server and the client down when there are inventory updates.
This can get particularly troublesome with pipeworks which
adds nodes that can mess around with inventories
automatically or with mods that have mobs with inventories
that actively use them.

* Optimize texture scaling cache

There is an io::path parameter passed by value in the
procedure used to add images converted from textures,
leading to slowdown when the image is not yet created and
the conversion is thus needed. The performance hit is
quite significant as io::path is similar to std::string
so convert the parameter to a const reference to get rid of
it.

* Optimize translation file loader

Use "std::string::append" when calculating the final index
for the translation table to avoid unnecessary temporary
strings. This speeds the translation file loader up
significantly as std::string uses heap allocation which
tends to be rather slow. Additionally, the heap is no
longer being littered by these unnecessary string
temporaries, increasing performance of code that gets
executed after the translation file loader finishes.

* Optimize server map saving

When the directory structure for the world data is created
during server map saving, an unnecessary value passing of
the directory name slows things down. Remove that overhead
by converting the offending parameter to a const reference.

diff --git a/src/client/content_cao.cpp b/src/client/content_cao.cpp
index b169ba75f73d909458cc68e11061d03015b1e78f..cf22aa0ed53447265b9cdd5d322e55e7a00b88c2 100644 (file)
--- a/src/client/content_cao.cpp
+++ b/src/client/content_cao.cpp
@@ -1062,7 +1062,7 @@ void GenericCAO::updateTexturePos()
        }
 }
 
-void GenericCAO::updateTextures(std::string mod)
+void GenericCAO::updateTextures(const std::string &modref)
 {
        ITextureSource *tsrc = m_client->tsrc();
 
@@ -1071,9 +1071,21 @@ void GenericCAO::updateTextures(std::string mod)
        bool use_anisotropic_filter = g_settings->getBool("anisotropic_filter");
 
        m_previous_texture_modifier = m_current_texture_modifier;
-       m_current_texture_modifier = mod;
+       m_current_texture_modifier = modref;
        m_glow = m_prop.glow;
 
+       // Create a reference to the copy of "modref" just created. The
+       // following code will then use this reference instead of the
+       // original parameter which was passed by reference. This is
+       // necessary as "modref" can be a class member and there is a swap on
+       // those class members which can get triggered by the rest of the
+       // code of this method. This is faster than passing the "mod" by
+       // value because it reuses the copy made by the assignment to
+       // m_current_texture_modifier for the "mod" instead of having two
+       // copies, one for "mod" and another one (created from "mod") for
+       // the m_current_texture_modifier class member.
+       const std::string &mod = m_current_texture_modifier;
+
        video::E_MATERIAL_TYPE material_type = (m_prop.use_texture_alpha) ?
                video::EMT_TRANSPARENT_ALPHA_CHANNEL : video::EMT_TRANSPARENT_ALPHA_CHANNEL_REF;
 

diff --git a/src/client/content_cao.h b/src/client/content_cao.h
index 3ce628d30c2104a3c09e245d5f11defa267d1c92..320607061dc2fd0320674d12ee9dad0cb399b4f5 100644 (file)
--- a/src/client/content_cao.h
+++ b/src/client/content_cao.h
@@ -225,9 +225,7 @@ public:
 
        void updateTexturePos();
 
-       // std::string copy is mandatory as mod can be a class member and there is a swap
-       // on those class members... do NOT pass by reference
-       void updateTextures(std::string mod);
+       void updateTextures(const std::string &modref);
 
        void updateAnimation();
 

diff --git a/src/client/guiscalingfilter.cpp b/src/client/guiscalingfilter.cpp
index 3b4377da53bab32b08070424fcfe51849ba8c870..312f939398e9f3dadab041590257d2ef5d5f9cc5 100644 (file)
--- a/src/client/guiscalingfilter.cpp
+++ b/src/client/guiscalingfilter.cpp
@@ -39,7 +39,7 @@ std::map<io::path, video::ITexture *> g_txrCache;
 /* Manually insert an image into the cache, useful to avoid texture-to-image
  * conversion whenever we can intercept it.
  */
-void guiScalingCache(io::path key, video::IVideoDriver *driver, video::IImage *value)
+void guiScalingCache(const io::path &key, video::IVideoDriver *driver, video::IImage *value)
 {
        if (!g_settings->getBool("gui_scaling_filter"))
                return;

diff --git a/src/client/guiscalingfilter.h b/src/client/guiscalingfilter.h
index 4661bf8daff3e4df3c4209392a29cec58cea1bb0..a5cd7851144a0cb6fb69a1809c7e86b7e01a5181 100644 (file)
--- a/src/client/guiscalingfilter.h
+++ b/src/client/guiscalingfilter.h
@@ -23,7 +23,7 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 /* Manually insert an image into the cache, useful to avoid texture-to-image
  * conversion whenever we can intercept it.
  */
-void guiScalingCache(io::path key, video::IVideoDriver *driver, video::IImage *value);
+void guiScalingCache(const io::path &key, video::IVideoDriver *driver, video::IImage *value);
 
 // Manually clear the cache, e.g. when switching to different worlds.
 void guiScalingCacheClear();

diff --git a/src/client/hud.cpp b/src/client/hud.cpp
index 1a2287a13bc872fe64948faaebcc6b27929eed60..cb58fb500e4cb354d614c0d582f78974db6543ea 100644 (file)
--- a/src/client/hud.cpp
+++ b/src/client/hud.cpp
@@ -372,7 +372,7 @@ void Hud::drawLuaElements(const v3s16 &camera_offset)
 }
 
 
-void Hud::drawStatbar(v2s32 pos, u16 corner, u16 drawdir, std::string texture,
+void Hud::drawStatbar(v2s32 pos, u16 corner, u16 drawdir, const std::string &texture,
                s32 count, v2s32 offset, v2s32 size)
 {
        const video::SColor color(255, 255, 255, 255);

diff --git a/src/client/hud.h b/src/client/hud.h
index e9bcdf4e23c39c6de340ee0c8ac92cf3ae34aad2..693d2adee18aad258804fbff691d1100ab46979e 100644 (file)
--- a/src/client/hud.h
+++ b/src/client/hud.h
@@ -81,7 +81,7 @@ public:
        void drawLuaElements(const v3s16 &camera_offset);
 
 private:
-       void drawStatbar(v2s32 pos, u16 corner, u16 drawdir, std::string texture,
+       void drawStatbar(v2s32 pos, u16 corner, u16 drawdir, const std::string &texture,
                        s32 count, v2s32 offset, v2s32 size = v2s32());
 
        void drawItems(v2s32 upperleftpos, v2s32 screen_offset, s32 itemcount,

diff --git a/src/client/tile.cpp b/src/client/tile.cpp
index 4911013aef0899688edfcbeda194ff03967db3b8..72f7358b1c6a2d2e6f53c0ab5b1619576f18dc53 100644 (file)
--- a/src/client/tile.cpp
+++ b/src/client/tile.cpp
@@ -131,7 +131,8 @@ std::string getTexturePath(const std::string &filename)
                Check from texture_path
        */
        for (const auto &path : getTextureDirs()) {
-               std::string testpath = path + DIR_DELIM + filename;
+               std::string testpath = path + DIR_DELIM;
+               testpath.append(filename);
                // Check all filename extensions. Returns "" if not found.
                fullpath = getImagePath(testpath);
                if (!fullpath.empty())

diff --git a/src/gui/guiChatConsole.cpp b/src/gui/guiChatConsole.cpp
index 1ccb4e6d1f7f76f0db61a48f98e055abc36fbf6c..42348beb33040900047537a973a31df72d5bece6 100644 (file)
--- a/src/gui/guiChatConsole.cpp
+++ b/src/gui/guiChatConsole.cpp
@@ -139,7 +139,7 @@ f32 GUIChatConsole::getDesiredHeight() const
        return m_desired_height_fraction;
 }
 
-void GUIChatConsole::replaceAndAddToHistory(std::wstring line)
+void GUIChatConsole::replaceAndAddToHistory(const std::wstring &line)
 {
        ChatPrompt& prompt = m_chat_backend->getPrompt();
        prompt.addToHistory(prompt.getLine());

diff --git a/src/gui/guiChatConsole.h b/src/gui/guiChatConsole.h
index ef8a8767387c2bc35c23bc3c0579064be85b2450..7be40e27c1472d0a9a488b1c974c80db6811a6f6 100644 (file)
--- a/src/gui/guiChatConsole.h
+++ b/src/gui/guiChatConsole.h
@@ -60,7 +60,7 @@ public:
        f32 getDesiredHeight() const;
 
        // Replace actual line when adding the actual to the history (if there is any)
-       void replaceAndAddToHistory(std::wstring line);
+       void replaceAndAddToHistory(const std::wstring &line);
 
        // Change how the cursor looks
        void setCursor(

diff --git a/src/gui/guiEngine.cpp b/src/gui/guiEngine.cpp
index 6030a5bfb5d3be0953691089b2693e6d273b26dd..f0a8f40eb230dc12d8255704abafecb42ed1048f 100644 (file)
--- a/src/gui/guiEngine.cpp
+++ b/src/gui/guiEngine.cpp
@@ -518,7 +518,7 @@ void GUIEngine::drawFooter(video::IVideoDriver *driver)
 }
 
 /******************************************************************************/
-bool GUIEngine::setTexture(texture_layer layer, std::string texturepath,
+bool GUIEngine::setTexture(texture_layer layer, const std::string &texturepath,
                bool tile_image, unsigned int minsize)
 {
        video::IVideoDriver *driver = RenderingEngine::get_video_driver();
@@ -593,7 +593,7 @@ void GUIEngine::updateTopLeftTextSize()
 }
 
 /******************************************************************************/
-s32 GUIEngine::playSound(SimpleSoundSpec spec, bool looped)
+s32 GUIEngine::playSound(const SimpleSoundSpec &spec, bool looped)
 {
        s32 handle = m_sound_manager->playSound(spec, looped);
        return handle;

diff --git a/src/gui/guiEngine.h b/src/gui/guiEngine.h
index 409ba94c498ae39f16606192633c2f2eeb75278b..0ff5030c0b93b677c91301ae95e2a59c373c305d 100644 (file)
--- a/src/gui/guiEngine.h
+++ b/src/gui/guiEngine.h
@@ -247,7 +247,7 @@ private:
         * @param layer draw layer to specify texture
         * @param texturepath full path of texture to load
         */
-       bool setTexture(texture_layer layer, std::string texturepath,
+       bool setTexture(texture_layer layer, const std::string &texturepath,
                        bool tile_image, unsigned int minsize);
 
        /**
@@ -296,7 +296,7 @@ private:
        clouddata   m_cloud;
 
        /** start playing a sound and return handle */
-       s32 playSound(SimpleSoundSpec spec, bool looped);
+       s32 playSound(const SimpleSoundSpec &spec, bool looped);
        /** stop playing a sound started with playSound() */
        void stopSound(s32 handle);
 

diff --git a/src/gui/guiFormSpecMenu.cpp b/src/gui/guiFormSpecMenu.cpp
index 92e6547659d9e05d9aa45cebd8b1392e6dc9c902..e2aed420cf835e6fd52068fcb7d91a831dceaf85 100644 (file)
--- a/src/gui/guiFormSpecMenu.cpp
+++ b/src/gui/guiFormSpecMenu.cpp
@@ -86,7 +86,7 @@ inline u32 clamp_u8(s32 value)
 GUIFormSpecMenu::GUIFormSpecMenu(JoystickController *joystick,
                gui::IGUIElement *parent, s32 id, IMenuManager *menumgr,
                Client *client, ISimpleTextureSource *tsrc, IFormSource *fsrc, TextDest *tdst,
-               std::string formspecPrepend,
+               const std::string &formspecPrepend,
                bool remap_dbl_click):
        GUIModalMenu(RenderingEngine::get_gui_env(), parent, id, menumgr),
        m_invmgr(client),

diff --git a/src/gui/guiFormSpecMenu.h b/src/gui/guiFormSpecMenu.h
index d75a108d4a9a36b8a1544055a673dd193a0e5406..33f88d8c03dad42d4b09ad7108d8620a4a4e7946 100644 (file)
--- a/src/gui/guiFormSpecMenu.h
+++ b/src/gui/guiFormSpecMenu.h
@@ -287,7 +287,7 @@ public:
                        ISimpleTextureSource *tsrc,
                        IFormSource* fs_src,
                        TextDest* txt_dst,
-                       std::string formspecPrepend,
+                       const std::string &formspecPrepend,
                        bool remap_dbl_click = true);
 
        ~GUIFormSpecMenu();

diff --git a/src/inventorymanager.cpp b/src/inventorymanager.cpp
index 51a472a569b49736252ac46b6a59168f68d1d771..24d1fa6ff470c7873455e7126ce153ff5aa96630 100644 (file)
--- a/src/inventorymanager.cpp
+++ b/src/inventorymanager.cpp
@@ -93,7 +93,7 @@ void InventoryLocation::deSerialize(std::istream &is)
        }
 }
 
-void InventoryLocation::deSerialize(std::string s)
+void InventoryLocation::deSerialize(const std::string &s)
 {
        std::istringstream is(s, std::ios::binary);
        deSerialize(is);

diff --git a/src/inventorymanager.h b/src/inventorymanager.h
index 30a82d4bf653267b7f862eccba0506a87a5bd554..06517f40faaa607ab39cf7ff34eed68b8e88d520 100644 (file)
--- a/src/inventorymanager.h
+++ b/src/inventorymanager.h
@@ -97,7 +97,7 @@ struct InventoryLocation
        std::string dump() const;
        void serialize(std::ostream &os) const;
        void deSerialize(std::istream &is);
-       void deSerialize(std::string s);
+       void deSerialize(const std::string &s);
 };
 
 struct InventoryAction;

diff --git a/src/map.cpp b/src/map.cpp
index 0114867e09e23478748f53e6da3cda0d69cbc7cf..3d1e7479043d739eeab4d74b1dad5bb8f3fe17a3 100644 (file)
--- a/src/map.cpp
+++ b/src/map.cpp
@@ -1717,7 +1717,7 @@ bool ServerMap::loadFromFolders() {
        return false;
 }
 
-void ServerMap::createDirs(std::string path)
+void ServerMap::createDirs(const std::string &path)
 {
        if (!fs::CreateAllDirs(path)) {
                m_dout<<"ServerMap: Failed to create directory "

diff --git a/src/map.h b/src/map.h
index 7ef34b2792c72638128e49d87ca1d4b90bc44497..251ac297fa8e5f3304b5d2cd8949611d34f46bc2 100644 (file)
--- a/src/map.h
+++ b/src/map.h
@@ -389,7 +389,7 @@ public:
                Misc. helper functions for fiddling with directory and file
                names when saving
        */
-       void createDirs(std::string path);
+       void createDirs(const std::string &path);
        // returns something like "map/sectors/xxxxxxxx"
        std::string getSectorDir(v2s16 pos, int layout = 2);
        // dirname: final directory name

diff --git a/src/server.cpp b/src/server.cpp
index 496170da3f9689f4300f2f94078b9385589f0f3f..7167a6686fc15346f8668cd419cac19a456c41c4 100644 (file)
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -3207,7 +3207,7 @@ bool Server::hudSetHotbarItemcount(RemotePlayer *player, s32 hotbar_itemcount)
        return true;
 }
 
-void Server::hudSetHotbarImage(RemotePlayer *player, std::string name)
+void Server::hudSetHotbarImage(RemotePlayer *player, const std::string &name)
 {
        if (!player)
                return;
@@ -3216,7 +3216,7 @@ void Server::hudSetHotbarImage(RemotePlayer *player, std::string name)
        SendHUDSetParam(player->getPeerId(), HUD_PARAM_HOTBAR_IMAGE, name);
 }
 
-void Server::hudSetHotbarSelectedImage(RemotePlayer *player, std::string name)
+void Server::hudSetHotbarSelectedImage(RemotePlayer *player, const std::string &name)
 {
        if (!player)
                return;

diff --git a/src/server.h b/src/server.h
index 5e58ac9e66688b5f9a5fe0c2593d3a67b1fb0dc6..4232653ebcd9053aca3e59cb13d2df41b4e1f131 100644 (file)
--- a/src/server.h
+++ b/src/server.h
@@ -296,8 +296,8 @@ public:
        bool hudChange(RemotePlayer *player, u32 id, HudElementStat stat, void *value);
        bool hudSetFlags(RemotePlayer *player, u32 flags, u32 mask);
        bool hudSetHotbarItemcount(RemotePlayer *player, s32 hotbar_itemcount);
-       void hudSetHotbarImage(RemotePlayer *player, std::string name);
-       void hudSetHotbarSelectedImage(RemotePlayer *player, std::string name);
+       void hudSetHotbarImage(RemotePlayer *player, const std::string &name);
+       void hudSetHotbarSelectedImage(RemotePlayer *player, const std::string &name);
 
        Address getPeerAddress(session_t peer_id);
 

diff --git a/src/translation.cpp b/src/translation.cpp
index 7ddd95591453c06a120e6396548462d221af6fa6..d17467ce75846112ef82038dda155c9b9ef2790c 100644 (file)
--- a/src/translation.cpp
+++ b/src/translation.cpp
@@ -149,6 +149,8 @@ void Translations::loadTranslation(const std::string &data)
                                    << wide_to_utf8(oword1) << "\"" << std::endl;
                }
 
-               m_translations[textdomain + L"|" + oword1] = oword2;
+               std::wstring translation_index = textdomain + L"|";
+               translation_index.append(oword1);
+               m_translations[translation_index] = oword2;
        }
 }

diff --git a/src/unittest/test_areastore.cpp b/src/unittest/test_areastore.cpp
index 62d446f5c076a189bbc2f8a295a4ae068354c0dc..a6d4706e44d55bd7cb649bbbd414bbe0c96128ea 100644 (file)
--- a/src/unittest/test_areastore.cpp
+++ b/src/unittest/test_areastore.cpp
@@ -152,7 +152,7 @@ void TestAreaStore::testSerialization()
                        1 + 2 +
                        6 + 6 + 2 + 6 +
                        6 + 6 + 2 + 6);
-       UASSERTEQ(std::string, str, str_wanted);
+       UASSERTEQ(const std::string &, str, str_wanted);
 
        std::istringstream is(str);
        store.deserialize(is);