Fix segfaults (#561)

* skString c_str contains string encoded in UTF8, but it was treated as UTF16

* ensure that managedString doesn't collect til the end of JNI call, also close manually at the end

skiko/src/commonMain/kotlin/org/jetbrains/skia/shaper/Shaper.kt

@@ -105,19 +105,20 @@ class Shaper internal constructor(ptr: NativePointer) : Managed(ptr, _FinalizerH
     fun shape(text: String, font: Font, opts: ShapingOptions, width: Float, offset: Point): TextBlob? {
         return try {
             Stats.onNativeCall()
-            val managedString = ManagedString(text)
-            val ptr = interopScope {
-                _nShapeBlob(
-                    _ptr,
-                    managedString._ptr,
-                    getPtr(font),
-                    optsFeaturesLen = opts.features?.size ?: 0,
-                    optsFeaturesIntArray = arrayOfFontFeaturesToInterop(opts.features),
-                    optsBooleanProps = opts._booleanPropsToInt(),
-                    width = width,
-                    offsetX = offset.x,
-                    offsetY = offset.y
-                )
+            val ptr = ManagedString(text).use { managedString ->
+                interopScope {
+                    _nShapeBlob(
+                        _ptr,
+                        managedString._ptr,
+                        getPtr(font),
+                        optsFeaturesLen = opts.features?.size ?: 0,
+                        optsFeaturesIntArray = arrayOfFontFeaturesToInterop(opts.features),
+                        optsBooleanProps = opts._booleanPropsToInt(),
+                        width = width,
+                        offsetX = offset.x,
+                        offsetY = offset.y
+                    )
+                }
             }
             if (NullPointer == ptr) null else TextBlob(ptr)
         } finally {

skiko/src/jvmMain/cpp/common/Font.cc

@@ -227,7 +227,10 @@ extern "C" JNIEXPORT jshort JNICALL Java_org_jetbrains_skia_FontKt__1nGetUTF32Gl
 extern "C" JNIEXPORT jint JNICALL Java_org_jetbrains_skia_FontKt__1nGetStringGlyphsCount
   (JNIEnv* env, jclass jclass, jlong ptr, jstring str, jint len) {
     SkFont* instance = reinterpret_cast<SkFont*>(static_cast<uintptr_t>(ptr));
-    return instance->countText(skString(env, str).c_str(), len * sizeof(jchar), SkTextEncoding::kUTF16);
+    const jchar* chars = env->GetStringCritical(str, nullptr);
+    jint result = instance->countText(chars, len * sizeof(jchar), SkTextEncoding::kUTF16);
+    env->ReleaseStringCritical(str, chars);
+    return result;
 }
 
 extern "C" JNIEXPORT void JNICALL Java_org_jetbrains_skia_FontKt__1nMeasureText
@@ -246,7 +249,10 @@ extern "C" JNIEXPORT jfloat JNICALL Java_org_jetbrains_skia_FontKt__1nMeasureTex
   (JNIEnv* env, jclass jclass, jlong ptr, jstring str, jint len, jlong paintPtr) {
     SkFont* instance = reinterpret_cast<SkFont*>(static_cast<uintptr_t>(ptr));
     SkPaint* paint = reinterpret_cast<SkPaint*>(static_cast<uintptr_t>(paintPtr));
-    return instance->measureText(skString(env, str).c_str(), len * sizeof(jchar), SkTextEncoding::kUTF16, nullptr, paint);
+    const jchar* chars = env->GetStringCritical(str, nullptr);
+    jfloat result = instance->measureText(chars, len * sizeof(jchar), SkTextEncoding::kUTF16, nullptr, paint);
+    env->ReleaseStringCritical(str, chars);
+    return result;
 }
 
 extern "C" JNIEXPORT void JNICALL Java_org_jetbrains_skia_FontKt__1nGetWidths