[API] Fix native loading by stopping creating tmpDir every time

imgui-binding/build.gradle

@@ -34,3 +34,19 @@ jar {
         attributes  'Automatic-Module-Name': 'imgui.binding'
     }
 }
+
+tasks.register('makePropertyResource') {
+    def directory = file "${buildDir}/resources/main/imgui/"
+    directory.mkdirs()
+    def propertyFile = file "${directory}/imgui-java.properties"
+    def props = new Properties()
+    if (propertyFile.exists()) {
+        propertyFile.withReader { props.load(it) }
+    }
+    props.setProperty("version", project.version)
+    propertyFile.withWriter { props.store(it, "imgui-java") }
+}
+
+processResources {
+    dependsOn makePropertyResource
+}

imgui-binding/src/main/java/imgui/ImGui.java

@@ -18,16 +18,18 @@
 import java.io.InputStream;
 import java.io.UncheckedIOException;
 import java.lang.ref.WeakReference;
+import java.nio.file.AccessDeniedException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.nio.file.StandardCopyOption;
+import java.util.Properties;
 
 public class ImGui {
     private static final String LIB_PATH_PROP = "imgui.library.path";
     private static final String LIB_NAME_PROP = "imgui.library.name";
     private static final String LIB_NAME_DEFAULT = System.getProperty("os.arch").contains("64") ? "imgui-java64" : "imgui-java";
-    private static final String LIB_TMP_DIR_PREFIX = "imgui-java-natives_" + System.currentTimeMillis();
+    private static final String LIB_TMP_DIR_PREFIX = "imgui-java-natives";
 
     private static final ImGuiContext IMGUI_CONTEXT;
     private static final ImGuiIO IMGUI_IO;
@@ -115,19 +117,43 @@ private static String tryLoadFromClasspath(final String fullLibName) {
                 return null;
             }
 
-            final Path tmpDir = Paths.get(System.getProperty("java.io.tmpdir")).resolve(LIB_TMP_DIR_PREFIX);
-            tmpDir.toFile().mkdirs();
+            String version = getVersionString();
+            if (version == null) {
+                version = "unknown";
+            }
+            final Path tmpDir = Paths.get(System.getProperty("java.io.tmpdir")).resolve(LIB_TMP_DIR_PREFIX).resolve(version);
+            if (!Files.exists(tmpDir)) {
+                Files.createDirectories(tmpDir);
+            }
 
             final Path libBin = tmpDir.resolve(fullLibName);
-            Files.copy(is, libBin, StandardCopyOption.REPLACE_EXISTING);
-            libBin.toFile().deleteOnExit();
+            try {
+                Files.copy(is, libBin, StandardCopyOption.REPLACE_EXISTING);
+            } catch (AccessDeniedException e) {
+                if (!Files.exists(libBin)) {
+                    throw e;
+                }
+            }
 
-            return libBin.toFile().getAbsolutePath();
+            return libBin.toAbsolutePath().toString();
         } catch (IOException e) {
             throw new UncheckedIOException(e);
         }
     }
 
+    private static String getVersionString() {
+        final Properties properties = new Properties();
+        try (InputStream is = ImGui.class.getResourceAsStream("/imgui/imgui-java.properties")) {
+            if (is != null) {
+                properties.load(is);
+                return properties.get("version").toString();
+            }
+        } catch (IOException e) {
+            throw new UncheckedIOException(e);
+        }
+        return null;
+    }
+
     /**
      * For internal usage.
      * Method is used to initiate static instantiation (loading of the native libraries etc.).