Proof of concept helper binding generation

.run/Generate helpers.run.xml

@@ -0,0 +1,12 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="Generate helpers" type="JetRunConfigurationType">
+    <option name="MAIN_CLASS_NAME" value="vipsffm.GenerateHelpers" />
+    <module name="vips-ffm.helper-generator.main" />
+    <shortenClasspath name="NONE" />
+    <option name="VM_PARAMETERS" value="--enable-preview" />
+    <method v="2">
+      <option name="Gradle.BeforeRunTask" enabled="true" tasks="compileJava" externalProjectPath="$PROJECT_DIR$/core" vmOptions="" scriptParameters="" />
+      <option name="Make" enabled="true" />
+    </method>
+  </configuration>
+</component>

build.gradle.kts

@@ -0,0 +1,3 @@
+plugins {
+    kotlin("jvm") version "2.0.10" apply false
+}

core/src/main/java/app/photofox/vipsffm/helper/VipsInvoker.java

@@ -0,0 +1,48 @@
+package app.photofox.vipsffm.helper;
+
+import app.photofox.vipsffm.generated.VipsRaw;
+
+import java.lang.foreign.Arena;
+import java.lang.foreign.MemoryLayout;
+import java.lang.foreign.MemorySegment;
+import java.lang.foreign.ValueLayout;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class VipsInvoker {
+
+    public static MemoryLayout[] makeInvokerVarargLayouts(VipsOption... args) {
+        List<ValueLayout> layouts = new ArrayList<>();
+        var listArgs = Arrays.stream(args).toList();
+        listArgs.forEach((arg) -> {
+            layouts.add(VipsRaw.C_POINTER);
+            switch (arg) {
+                case VipsStringOption _ -> layouts.add(VipsRaw.C_POINTER);
+                case VipsIntOption _ -> layouts.add(VipsRaw.C_INT);
+            }
+        });
+        layouts.add(VipsRaw.C_POINTER);
+        return layouts.toArray(MemoryLayout[]::new);
+    }
+
+    public static Object[] makeInvokerVarargObjects(Arena arena, VipsOption... args) {
+        var invokeArgs = new ArrayList<>();
+        var listArgs = Arrays.stream(args).toList();
+        listArgs.forEach((arg) -> {
+            var keyCString = arena.allocateFrom(arg.key());
+            invokeArgs.add(keyCString);
+            switch (arg) {
+                case VipsStringOption stringOption -> {
+                    var valueCString = arena.allocateFrom(stringOption.value());
+                    invokeArgs.add(valueCString);
+                }
+                case VipsIntOption intOption -> {
+                    invokeArgs.add(intOption.value());
+                }
+            }
+        });
+        invokeArgs.add(MemorySegment.NULL);
+        return invokeArgs.toArray(Object[]::new);
+    }
+}

core/src/main/java/app/photofox/vipsffm/helper/VipsValidation.java

@@ -0,0 +1,40 @@
+package app.photofox.vipsffm.helper;
+
+import app.photofox.vipsffm.generated.VipsRaw;
+
+import java.lang.foreign.*;
+
+public class VipsValidation {
+
+    public static boolean isValidPointer(MemorySegment memorySegment) {
+        return memorySegment != MemorySegment.NULL && memorySegment.address() != 0;
+    }
+
+    public static boolean isValidResult(int result) {
+        return result == 0;
+    }
+
+    public static void throwVipsError(String commandName) throws VipsError {
+        var errorBuffer = VipsRaw.vips_error_buffer();
+        if (!isValidPointer(errorBuffer)) {
+            throw new VipsError("failed to run vips command " + commandName);
+        }
+
+        var errorString = errorBuffer.getString(0);
+        throw new VipsError("failed to run vips command " + commandName + ": " + errorString);
+    }
+
+    public static void throwInvalidInputError(String commandName, String argName) throws VipsError {
+        throw new VipsError("invalid input provided to command " + commandName + " argument " + argName);
+    }
+
+    public static void throwInvalidOutputError(String commandName, String argName) throws VipsError {
+        var errorBuffer = VipsRaw.vips_error_buffer();
+        if (!isValidPointer(errorBuffer)) {
+            throw new VipsError("failed to run vips command " + commandName);
+        }
+
+        var errorString = errorBuffer.getString(0);
+        throw new VipsError("invalid output pointer from command " + commandName + " argument " + argName + ": " + errorString);
+    }
+}

generate_ffm_bindings.sh

@@ -66,3 +66,5 @@ set -x
 --library "vips" \
 @includes_filtered.txt \
 "$LIBVIPS_ENTRY_PATH"
+
+./gradlew clean helper-generator:run

helper-generator/build.gradle.kts

@@ -0,0 +1,50 @@
+@file:Suppress("UnstableApiUsage")
+
+import org.gradle.api.tasks.testing.logging.TestExceptionFormat
+import org.gradle.api.tasks.testing.logging.TestLogEvent
+
+plugins {
+    kotlin("jvm")
+    application
+}
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation(project(":core"))
+    implementation(platform("org.slf4j:slf4j-bom:2.0.16"))
+    implementation("com.squareup:javapoet:1.13.0")
+    implementation("org.slf4j:slf4j-api")
+    implementation("org.slf4j:slf4j-simple")
+}
+
+java {
+    toolchain {
+        languageVersion.set(JavaLanguageVersion.of(22))
+    }
+}
+
+testing {
+    suites {
+        val test by getting(JvmTestSuite::class) {
+            useKotlinTest("2.0.0")
+            testType = TestSuiteType.UNIT_TEST
+        }
+    }
+}
+
+tasks.withType<Test> {
+    testLogging {
+        events = TestLogEvent.values().toSet() - TestLogEvent.STARTED
+        exceptionFormat = TestExceptionFormat.FULL
+    }
+    outputs.upToDateWhen { false }
+}
+
+application {
+    mainClass = "vipsffm.GenerateHelpers"
+    applicationDefaultJvmArgs = listOf("--enable-preview")
+    tasks.run.get().workingDir = rootProject.projectDir
+}