Add support for equality operators via new 'requires' keyword for interfaces

.github/workflows/main.yaml

@@ -10,15 +10,17 @@ on:
 jobs:
   build:
     runs-on: ubuntu-latest
+    env:
+      JAVA_OPTS: -Xms2048M -Xmx2048M -Xss6M -XX:ReservedCodeCacheSize=256M -Dfile.encoding=UTF-8
     steps:
       - uses: actions/checkout@v4
-      - name: Caching dependencies
-        uses: actions/cache@v3
+      - name: Setup JDK
+        uses: actions/setup-java@v4
         with:
-          path: |
-            ~/.sbt
-            ~/.ivy2
-          key: scala-build-deps
+          distribution: temurin
+          java-version: 17
+          cache: sbt
+      - uses: sbt/setup-sbt@v1
       - name: Building
         run: sbt assembly
       - uses: actions/upload-artifact@v4
@@ -29,11 +31,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - name: Caching dependencies
-        uses: actions/cache@v3
+      - name: Setup JDK
+        uses: actions/setup-java@v4
         with:
-          path: ~/.sbt
-          key: scala-fmt-deps
+          distribution: temurin
+          java-version: 17
+          cache: sbt
+      - uses: sbt/setup-sbt@v1
       - name: "Format check generator"
         run: sbt scalafmtCheck
       - name: "Format check integration test"
@@ -43,13 +47,13 @@ jobs:
     needs: [build, formatCheck]
     steps:
       - uses: actions/checkout@v4
-      - name: Caching dependencies
-        uses: actions/cache@v3
+      - name: Setup JDK
+        uses: actions/setup-java@v4
         with:
-          path: |
-            ~/.sbt
-            ~/.ivy2
-          key: scala-build-deps
+          distribution: temurin
+          java-version: 17
+          cache: sbt
+      - uses: sbt/setup-sbt@v1
       - uses: actions/download-artifact@v4
         with:
           name: djinni-generator
@@ -61,15 +65,17 @@ jobs:
 
   buildWindows:
     runs-on: windows-latest
+    env:
+      JAVA_OPTS: -Xms2048M -Xmx2048M -Xss6M -XX:ReservedCodeCacheSize=256M -Dfile.encoding=UTF-8
     steps:
       - uses: actions/checkout@v4
-      - name: Caching dependencies
-        uses: actions/cache@v3
+      - name: Setup JDK
+        uses: actions/setup-java@v4
         with:
-          path: |
-            ~/.sbt
-            ~/.ivy2
-          key: scala-build-deps-windows
+          distribution: temurin
+          java-version: 17
+          cache: sbt
+      - uses: sbt/setup-sbt@v1
       - name: Building
         run: sbt assembly
       - name: Testing

.github/workflows/release.yaml

@@ -8,15 +8,17 @@ name: Upload Release Assets
 jobs:
   buildUnix:
     runs-on: ubuntu-latest
+    env:
+      JAVA_OPTS: -Xms2048M -Xmx2048M -Xss6M -XX:ReservedCodeCacheSize=256M -Dfile.encoding=UTF-8
     steps:
       - uses: actions/checkout@v4
-      - name: Caching dependencies
-        uses: actions/cache@v3
+      - name: Setup JDK
+        uses: actions/setup-java@v4
         with:
-          path: |
-            ~/.sbt
-            ~/.ivy2
-          key: scala-build-deps
+          distribution: temurin
+          java-version: 17
+          cache: sbt
+      - uses: sbt/setup-sbt@v1
       - name: Building
         run: sbt assembly
       - uses: actions/upload-artifact@v4

src/main/scala/djinni/CppGenerator.scala

@@ -15,6 +15,7 @@
 
 package djinni
 
+import djinni.ast.Interface.RequiresType
 import djinni.ast.Record.DerivingType
 import djinni.ast._
 import djinni.generatorTools._
@@ -744,6 +745,38 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
                   .mkString("(", ", ", ")")}$constFlag = 0;")
             }
           }
+          // Requires
+          if (!i.requiresTypes.isEmpty) {
+            if (i.ext.cpp) {
+              w.wl
+              w.w("class Operators").bracedSemi {
+                w.wlOutdent("public:")
+                if (i.requiresTypes.contains(RequiresType.Eq)) {
+                  w.wl(
+                    s"static bool equals(const ${self}& left, const ${self}& right);"
+                  )
+                  w.wl
+                  w.wl(s"static int32_t hashCode(const ${self}& object);")
+                }
+              }
+            }
+
+            // TODO: how to apply formating rules to equals/compareTo/hashCode?
+
+            if (i.ext.java) {
+              if (i.requiresTypes.contains(RequiresType.Eq)) {
+                w.wl
+                w.wl(s"virtual bool equals(const ${self}& other) const = 0;")
+                w.wl
+                w.wl(s"virtual int hashCode() const = 0;")
+              }
+
+              if (i.requiresTypes.contains(RequiresType.Ord)) {
+                w.wl
+                w.wl(s"virtual int compareTo(const ${self}& other) const = 0;")
+              }
+            }
+          }
         }
       }
     )

src/main/scala/djinni/JNIGenerator.scala

@@ -15,6 +15,7 @@
 
 package djinni
 
+import djinni.ast.Interface.RequiresType
 import djinni.ast._
 import djinni.generatorTools._
 import djinni.meta._
@@ -591,6 +592,52 @@ class JNIGenerator(spec: Spec) extends Generator(spec) {
             }
           )
         }
+        if (i.requiresTypes.contains(RequiresType.Eq)) {
+          val equalsName = "native_operator_equals"
+          val equalsMethodNameMunged = equalsName.replaceAllLiterally("_", "_1")
+          w.wl(
+            s"CJNIEXPORT jboolean JNICALL ${prefix}_00024CppProxy_$equalsMethodNameMunged(JNIEnv* jniEnv, jobject /*this*/, jlong nativeRef, jobject j_obj)"
+          ).braced {
+            w.w("try")
+              .bracedEnd(
+                s" JNI_TRANSLATE_EXCEPTIONS_RETURN(jniEnv, 0 /* value doesn't matter */)"
+              ) {
+                w.wl(s"DJINNI_FUNCTION_PROLOGUE1(jniEnv, nativeRef);")
+                w.wl(
+                  s"const auto& ref = ::djinni::objectFromHandleAddress<$cppSelf>(nativeRef);"
+                )
+                w.wl(
+                  s"const auto& otherRef = ${withNs(Some(spec.jniNamespace), jniSelf)}::toCpp(jniEnv, j_obj);"
+                )
+                w.wl(s"auto r = $cppSelf::Operators::equals(*ref, *otherRef);")
+                w.wl(
+                  "return ::djinni::release(::djinni::Bool::fromCpp(jniEnv, r));"
+                )
+              }
+          }
+
+          val hashCodeName = "native_hash_code"
+          val hashCodeMethodNameMunged =
+            hashCodeName.replaceAllLiterally("_", "_1")
+          w.wl(
+            s"CJNIEXPORT jint JNICALL ${prefix}_00024CppProxy_$hashCodeMethodNameMunged(JNIEnv* jniEnv, jobject /*this*/, jlong nativeRef)"
+          ).braced {
+            w.w("try")
+              .bracedEnd(
+                s" JNI_TRANSLATE_EXCEPTIONS_RETURN(jniEnv, 0 /* value doesn't matter */)"
+              ) {
+                w.wl(s"DJINNI_FUNCTION_PROLOGUE1(jniEnv, nativeRef);")
+                w.wl(
+                  s"const auto& ref = ::djinni::objectFromHandleAddress<$cppSelf>(nativeRef);"
+                )
+                w.wl(s"auto r = $cppSelf::Operators::hashCode(*ref);")
+                w.wl(
+                  "return ::djinni::release(::djinni::I32::fromCpp(jniEnv, r));"
+                )
+              }
+          }
+
+        }
       }
     }
 

src/main/scala/djinni/JavaGenerator.scala

@@ -15,6 +15,7 @@
 
 package djinni
 
+import djinni.ast.Interface.RequiresType
 import djinni.ast.Record.DerivingType
 import djinni.ast._
 import djinni.generatorTools._
@@ -196,6 +197,13 @@ class JavaGenerator(spec: Spec) extends Generator(spec) {
 
         javaAnnotationHeader.foreach(w.wl)
 
+        val interfaces = scala.collection.mutable.ArrayBuffer[String]()
+        if (i.requiresTypes.contains(RequiresType.Ord))
+          interfaces += s"Comparable<$javaClass>"
+        val implementsSection =
+          if (interfaces.isEmpty) ""
+          else " implements " + interfaces.mkString(", ")
+
         // Generate an interface or an abstract class depending on whether the use
         // of Java interfaces was requested.
         val classPrefix =
@@ -206,7 +214,7 @@ class JavaGenerator(spec: Spec) extends Generator(spec) {
         val innerClassAccessibility =
           if (spec.javaGenerateInterfaces) "" else "private "
         w.w(
-          s"${javaClassAccessModifierString}$classPrefix $javaClass$typeParamList"
+          s"${javaClassAccessModifierString}$classPrefix $javaClass$typeParamList$implementsSection"
         ).braced {
           val skipFirst = SkipFirst()
           generateJavaConstants(w, i.consts, spec.javaGenerateInterfaces)
@@ -262,6 +270,24 @@ class JavaGenerator(spec: Spec) extends Generator(spec) {
             }
           }
 
+          if (i.ext.java) {
+            if (i.requiresTypes.contains(RequiresType.Eq)) {
+              w.wl
+              w.wl("@Override")
+              if (i.ext.java) {
+                w.wl("public abstract boolean equals(@Nullable Object obj);")
+              }
+            }
+
+            if (i.requiresTypes.contains(RequiresType.Ord)) {
+              w.wl
+              w.wl("@Override")
+              if (i.ext.java) {
+                w.wl(s"public abstract int compareTo($javaClass other);")
+              }
+            }
+          }
+
           if (i.ext.cpp) {
             w.wl
             javaAnnotationHeader.foreach(w.wl)
@@ -305,7 +331,7 @@ class JavaGenerator(spec: Spec) extends Generator(spec) {
                   m.params.map(p => idJava.local(p.ident)).mkString(", ")
                 val meth = idJava.method(m.ident)
                 w.wl
-                w.wl(s"@Override")
+                w.wl("@Override")
                 w.wl(s"public $ret $meth($params)$throwException").braced {
                   w.wl(
                     "assert !this.destroyed.get() : \"trying to use a destroyed object\";"
@@ -319,6 +345,46 @@ class JavaGenerator(spec: Spec) extends Generator(spec) {
                 )
               }
 
+              if (i.requiresTypes.contains(RequiresType.Eq)) {
+                // equals() override
+                w.wl
+                w.wl("@Override")
+                val nullableAnnotation =
+                  javaNullableAnnotation.map(_ + " ").getOrElse("")
+                w.w(s"public boolean equals(${nullableAnnotation}Object obj)")
+                  .braced {
+                    w.wl(
+                      "assert !this.destroyed.get() : \"trying to use a destroyed object\";"
+                    )
+                    w.wl
+                    w.w(s"if (!(obj instanceof $javaClass))").braced {
+                      w.wl("return false;")
+                    }
+                    w.wl
+                    w.wl(
+                      s"return native_operator_equals(this.nativeRef, ($javaClass)obj);"
+                    )
+                  }
+                w.wl(
+                  s"private native boolean native_operator_equals(long _nativeRef, $javaClass other);"
+                )
+
+                // hashCode() override
+                w.wl
+                w.wl("@Override")
+                w.w("public int hashCode()").braced {
+                  w.wl(
+                    "assert !this.destroyed.get() : \"trying to use a destroyed object\";"
+                  )
+                  w.wl(
+                    s"return native_hash_code(this.nativeRef);"
+                  )
+                }
+                w.wl(
+                  s"private native int native_hash_code(long _nativeRef);"
+                )
+              }
+
               // Declare a native method for each of the interface's static methods.
               for (m <- i.methods if m.static) {
                 skipFirst { w.wl }

src/main/scala/djinni/ast/ast.scala

@@ -16,6 +16,7 @@
 package djinni.ast
 
 import djinni.ast.Record.DerivingType.DerivingType
+import djinni.ast.Interface.RequiresType.RequiresType
 import djinni.meta.MExpr
 import djinni.syntax.Loc
 
@@ -110,9 +111,14 @@ object Record {
 case class Interface(
     ext: Ext,
     methods: Seq[Interface.Method],
-    consts: Seq[Const]
+    consts: Seq[Const],
+    requiresTypes: Set[RequiresType]
 ) extends TypeDef
 object Interface {
+  object RequiresType extends Enumeration {
+    type RequiresType = Value
+    val Eq, Ord = Value
+  }
   case class Method(
       ident: Ident,
       params: Seq[Field],