common: STM32 portability enhancement

Some systems such as micro-processor might not support
the thread feature on the system.

Enhance the portability by compiling the thorvg with toggling the
threading depepdency through the build option.

For this, thorvg newly introduced the internal Key/ScopedLock abstraction
for transparent thread-locking dependnecy.

To turn off the thread feature, please use the next build option:

$meson setup build -Dthreads=false ...

Note that, the thread feature is enabled in default.
Turning off the thread feature could reduce the binary size by 7kb.

issue: thorvg#1900

Author: hermet

meson.build

@@ -13,6 +13,11 @@ add_project_arguments('-DEXAMPLE_DIR="@0@/src/examples/resources"'.format(src_di
 
 config_h.set_quoted('THORVG_VERSION_STRING', meson.project_version())
 
+#Multi-Tasking
+if get_option('threads') == true
+  config_h.set10('THORVG_THREAD_SUPPORT', true)
+endif
+
 #Engines
 if get_option('engines').contains('sw') == true
     config_h.set10('THORVG_SW_RASTER_SUPPORT', true)
@@ -132,32 +137,34 @@ Summary:
     ThorVG version:        @0@
     Build Type:            @1@
     Prefix:                @2@
-    SIMD Instruction:      @3@
-    Raster Engine (SW):    @4@
-    Raster Engine (GL):    @5@
-    Raster Engine (WG):    @6@
-    Loader (TVG):          @7@
-    Loader (SVG):          @8@
-    Loader (TTF):          @9@
-    Loader (LOTTIE):       @10@
-    Loader (PNG):          @11@
-    Loader (JPG):          @12@
-    Loader (WEBP_BETA):    @13@
-    Saver (TVG):           @14@
-    Saver (GIF):           @15@
-    Binding (CAPI):        @16@
-    Binding (WASM_BETA):   @17@
-    Log Message:           @18@
-    Tests:                 @19@
-    Examples:              @20@
-    Tool (Svg2Tvg):        @21@
-    Tool (Svg2Png):        @22@
-    Tool (Lottie2Gif):     @23@
+    Multi-Tasking:         @3@
+    SIMD Instruction:      @4@
+    Raster Engine (SW):    @5@
+    Raster Engine (GL):    @6@
+    Raster Engine (WG):    @7@
+    Loader (TVG):          @8@
+    Loader (SVG):          @9@
+    Loader (TTF):          @10@
+    Loader (LOTTIE):       @11@
+    Loader (PNG):          @12@
+    Loader (JPG):          @13@
+    Loader (WEBP_BETA):    @14@
+    Saver (TVG):           @15@
+    Saver (GIF):           @16@
+    Binding (CAPI):        @17@
+    Binding (WASM_BETA):   @18@
+    Log Message:           @19@
+    Tests:                 @20@
+    Examples:              @21@
+    Tool (Svg2Tvg):        @22@
+    Tool (Svg2Png):        @23@
+    Tool (Lottie2Gif):     @24@
 
 '''.format(
         meson.project_version(),
         get_option('buildtype'),
         get_option('prefix'),
+        get_option('threads'),
         simd_type,
         get_option('engines').contains('sw'),
         get_option('engines').contains('gl_beta'),

meson_options.txt

@@ -16,6 +16,11 @@ option('savers',
    value: [''],
    description: 'Enable File Savers in thorvg')
 
+option('threads',
+   type: 'boolean',
+   value: true,
+   description: 'Enable the multi-threading task scheduler in thorvg')
+
 option('vector',
    type: 'boolean',
    value: false,

src/common/meson.build

@@ -1,9 +1,10 @@
 source_file = [
    'tvgArray.h',
    'tvgBezier.h',
-   'tvgFormat.h',
    'tvgCompressor.h',
+   'tvgFormat.h',
    'tvgInlist.h',
+   'tvgLock.h',
    'tvgMath.h',
    'tvgStr.h',
    'tvgBezier.cpp',

src/common/tvgLock.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2024 the ThorVG project. All rights reserved.
+
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef _TVG_LOCK_H_
+#define _TVG_LOCK_H_
+
+#ifdef THORVG_THREAD_SUPPORT
+
+#include <mutex>
+
+namespace tvg {
+
+    struct Key
+    {
+        std::mutex mtx;
+    };
+
+    struct ScopedLock
+    {
+        Key* key = nullptr;
+
+        ScopedLock(Key& key)
+        {
+            key.mtx.lock();
+            this->key = &key;
+        }
+
+        ~ScopedLock()
+        {
+            key->mtx.unlock();
+        }
+    };
+
+}
+
+#else //THORVG_THREAD_SUPPORT
+
+namespace tvg {
+
+    struct Key {};
+
+    struct ScopedLock
+    {
+        ScopedLock(Key& key) {}
+    };
+
+}
+
+#endif //THORVG_THREAD_SUPPORT
+
+#endif //_TVG_LOCK_H_

src/meson.build

@@ -42,7 +42,8 @@ subdir('loaders')
 subdir('savers')
 
 thorvg_lib_dep = [common_dep, utils_dep, loader_dep, saver_dep]
-if host_machine.system() != 'windows' and host_machine.system() != 'android'
+
+if get_option('threads') == true and host_machine.system() != 'windows' and host_machine.system() != 'android'
     thread_dep = meson.get_compiler('cpp').find_library('pthread')
     thorvg_lib_dep += [thread_dep]
 endif

src/renderer/sw_engine/tvgSwRaster.cpp

@@ -1855,7 +1855,7 @@ void rasterUnpremultiply(Surface* surface)
 
 void rasterPremultiply(Surface* surface)
 {
-    unique_lock<mutex> lock{surface->mtx};
+    ScopedLock lock(surface->key);
     if (surface->premultiplied || (surface->channelSize != sizeof(uint32_t))) return;
     surface->premultiplied = true;
 
@@ -1936,7 +1936,7 @@ bool rasterImage(SwSurface* surface, SwImage* image, const RenderMesh* mesh, con
 
 bool rasterConvertCS(Surface* surface, ColorSpace to)
 {
-    unique_lock<mutex> lock{surface->mtx};
+    ScopedLock lock(surface->key);
     if (surface->cs == to) return true;
 
     //TOOD: Support SIMD accelerations

src/renderer/tvgLoader.cpp

@@ -24,6 +24,7 @@
 
 #include "tvgInlist.h"
 #include "tvgLoader.h"
+#include "tvgLock.h"
 
 #ifdef THORVG_SVG_LOADER_SUPPORT
     #include "tvgSvgLoader.h"
@@ -65,7 +66,7 @@ uint64_t HASH_KEY(const char* data, uint64_t size)
 /* Internal Class Implementation                                        */
 /************************************************************************/
 
-static mutex mtx;
+static Key key;
 static Inlist<LoadModule> _activeLoaders;
 
 
@@ -211,7 +212,7 @@ static LoadModule* _findByType(const string& mimeType)
 
 static LoadModule* _findFromCache(const string& path)
 {
-    unique_lock<mutex> lock{mtx};
+    ScopedLock lock(key);
 
     auto loader = _activeLoaders.head;
 
@@ -231,7 +232,7 @@ static LoadModule* _findFromCache(const char* data, uint32_t size, const string&
     auto type = _convert(mimeType);
     if (type == FileType::Unknown) return nullptr;
 
-    unique_lock<mutex> lock{mtx};
+    ScopedLock lock(key);
     auto loader = _activeLoaders.head;
 
     auto key = HASH_KEY(data, size);
@@ -279,7 +280,7 @@ bool LoaderMgr::retrieve(LoadModule* loader)
     if (!loader) return false;
     if (loader->close()) {
         {
-            unique_lock<mutex> lock{mtx};
+            ScopedLock lock(key);
             _activeLoaders.remove(loader);
         }
         delete(loader);
@@ -298,7 +299,7 @@ LoadModule* LoaderMgr::loader(const string& path, bool* invalid)
         if (loader->open(path)) {
             loader->hashpath = strdup(path.c_str());
             {
-                unique_lock<mutex> lock{mtx};
+                ScopedLock lock(key);
                 _activeLoaders.back(loader);
             }
             return loader;
@@ -340,7 +341,7 @@ LoadModule* LoaderMgr::loader(const char* data, uint32_t size, const string& mim
         if (auto loader = _findByType(mimeType)) {
             if (loader->open(data, size, rpath, copy)) {
                 loader->hashkey = HASH_KEY(data, size);                
-                unique_lock<mutex> lock{mtx};
+                ScopedLock lock(key);
                 _activeLoaders.back(loader);
                 return loader;
             } else {
@@ -356,7 +357,7 @@ LoadModule* LoaderMgr::loader(const char* data, uint32_t size, const string& mim
                 if (loader->open(data, size, rpath, copy)) {
                     loader->hashkey = HASH_KEY(data, size);
                     {
-                        unique_lock<mutex> lock{mtx};
+                        ScopedLock lock(key);
                         _activeLoaders.back(loader);
                     }
                     return loader;
@@ -379,7 +380,7 @@ LoadModule* LoaderMgr::loader(const uint32_t *data, uint32_t w, uint32_t h, bool
     if (loader->open(data, w, h, premultiplied, copy)) {
         loader->hashkey = HASH_KEY((const char*)data, w * h);
         {
-            unique_lock<mutex> lock{mtx};
+            ScopedLock lock(key);
             _activeLoaders.back(loader);
         }
         return loader;

src/renderer/tvgRender.h

@@ -23,9 +23,9 @@
 #ifndef _TVG_RENDER_H_
 #define _TVG_RENDER_H_
 
-#include <mutex>
 #include "tvgCommon.h"
 #include "tvgArray.h"
+#include "tvgLock.h"
 
 namespace tvg
 {
@@ -54,7 +54,7 @@ struct Surface
         uint32_t* buf32;            //for explicit 32bits channels
         uint8_t*  buf8;             //for explicit 8bits grayscale
     };
-    mutex mtx;                      //reserved for the thread safety
+    Key key;                        //a reserved lock for the thread safety
     uint32_t stride = 0;
     uint32_t w = 0, h = 0;
     ColorSpace cs = ColorSpace::Unsupported;