Added support for constexpr for primitives in header files

CONTRIBUTORS

@@ -5,4 +5,5 @@ The complete list of contributors can be identified through
 Git history.
 
 - Google Inc.
+- Microsoft Corp.
 

src/source/BaseObjcGenerator.scala

@@ -57,7 +57,7 @@ abstract class BaseObjcGenerator(spec: Spec) extends Generator(spec) {
       case d: Double => w.w(boxedPrimitive(ty) + d.toString)
       case b: Boolean => w.w(boxedPrimitive(ty) + (if (b) "YES" else "NO"))
       case s: String => w.w("@" + s)
-      case e: EnumValue => w.w(idObjc.enum(e.ty + "_" + e.name))
+      case e: EnumValue => w.w(marshal.typename(ty) + idObjc.enum(e.name))
       case v: ConstRef => w.w(selfName + idObjc.const (v.name))
       case z: Map[_, _] => { // Value is record
       val recordMdef = ty.resolved.base.asInstanceOf[MDef]

src/source/CppGenerator.scala

@@ -112,11 +112,35 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
     })
   }
 
+  def shouldConstexpr(c: Const) = {
+    // Make sure we don't constexpr optionals as some might not support it
+    val canConstexpr = c.ty.resolved.base match {
+      case p: MPrimitive if c.ty.resolved.base != MOptional => true
+      case _ => false
+    }
+    canConstexpr
+  }
+
   def generateHppConstants(w: IndentWriter, consts: Seq[Const]) = {
     for (c <- consts) {
+      // set value in header if can constexpr (only primitives)
+      var constexpr = shouldConstexpr(c)
+      var constValue = ";"
+      if (constexpr) {
+        constValue = c.value match {
+        case l: Long => " = " + l.toString + ";"
+        case d: Double if marshal.fieldType(c.ty) == "float" => " = " + d.toString + "f;"
+        case d: Double => " = " + d.toString + ";"
+        case b: Boolean => if (b) " = true;" else " = false;"
+        case _ => ";"
+        }
+      }
+      val constFieldType = if (constexpr) s"constexpr ${marshal.fieldType(c.ty)}" else s"${marshal.fieldType(c.ty)} const"
+
+      // Write code to the header file
       w.wl
       writeDoc(w, c.doc)
-      w.wl(s"static ${marshal.fieldType(c.ty)} const ${idCpp.const(c.ident)};")
+      w.wl(s"static ${constFieldType} ${idCpp.const(c.ident)}${constValue}")
     }
   }
 
@@ -127,7 +151,7 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
       case d: Double => w.w(d.toString)
       case b: Boolean => w.w(if (b) "true" else "false")
       case s: String => w.w("{" + s + "}")
-      case e: EnumValue => w.w(marshal.typename(ty) + "::" + idCpp.enum(e.ty.name + "_" + e.name))
+      case e: EnumValue => w.w(marshal.typename(ty) + "::" + idCpp.enum(e.name))
       case v: ConstRef => w.w(selfName + "::" + idCpp.const(v))
       case z: Map[_, _] => { // Value is record
         val recordMdef = ty.resolved.base.asInstanceOf[MDef]
@@ -150,8 +174,12 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
     val skipFirst = SkipFirst()
     for (c <- consts) {
       skipFirst{ w.wl }
-      w.w(s"${marshal.fieldType(c.ty)} const $selfName::${idCpp.const(c.ident)} = ")
-      writeCppConst(w, c.ty, c.value)
+      if (shouldConstexpr(c)){
+        w.w(s"${marshal.fieldType(c.ty)} const $selfName::${idCpp.const(c.ident)}")
+      } else {
+        w.w(s"${marshal.fieldType(c.ty)} const $selfName::${idCpp.const(c.ident)} = ")
+        writeCppConst(w, c.ty, c.value)
+      }
       w.wl(";")
     }
   }

test-suite/djinni/constants.djinni

@@ -1,3 +1,9 @@
+# enum for use in constants
+constant_enum = enum {
+    some_value;
+    some_other_value;
+}
+
 # Record for use in constants
 constant_record = record {
     some_integer: i32;
@@ -18,6 +24,8 @@ constants = record {
     #   Indented third line of multi-line documentation.)
     const f64_constant: f64 = 5.0;
 
+    const const_enum: constant_enum = constant_enum::some_value;
+
     const opt_bool_constant: optional<bool> = true;
     const opt_i8_constant: optional<i8> = 1;
     # opt_i16_constant has documentation.
@@ -59,6 +67,8 @@ constants_interface = interface +c {
     const f32_constant: f32 = 5.0;
     const f64_constant: f64 = 5.0;
 
+    const const_enum: constant_enum = constant_enum::some_value;
+
     const opt_bool_constant: optional<bool> = true;
     const opt_i8_constant: optional<i8> = 1;
     # opt_i16_constant has documentation.

test-suite/generated-src/cpp/constant_enum.hpp

@@ -0,0 +1,26 @@
+// AUTOGENERATED FILE - DO NOT MODIFY!
+// This file generated by Djinni from constants.djinni
+
+#pragma once
+
+#include <functional>
+
+namespace testsuite {
+
+enum class constant_enum : int {
+    SOME_VALUE,
+    SOME_OTHER_VALUE,
+};
+
+}  // namespace testsuite
+
+namespace std {
+
+template <>
+struct hash<::testsuite::constant_enum> {
+    size_t operator()(::testsuite::constant_enum type) const {
+        return std::hash<int>()(static_cast<int>(type));
+    }
+};
+
+}  // namespace std

test-suite/generated-src/cpp/constants.cpp

@@ -5,19 +5,21 @@
 
 namespace testsuite {
 
-bool const Constants::BOOL_CONSTANT = true;
+bool const Constants::BOOL_CONSTANT;
 
-int8_t const Constants::I8_CONSTANT = 1;
+int8_t const Constants::I8_CONSTANT;
 
-int16_t const Constants::I16_CONSTANT = 2;
+int16_t const Constants::I16_CONSTANT;
 
-int32_t const Constants::I32_CONSTANT = 3;
+int32_t const Constants::I32_CONSTANT;
 
-int64_t const Constants::I64_CONSTANT = 4;
+int64_t const Constants::I64_CONSTANT;
 
-float const Constants::F32_CONSTANT = 5.0f;
+float const Constants::F32_CONSTANT;
 
-double const Constants::F64_CONSTANT = 5.0;
+double const Constants::F64_CONSTANT;
+
+constant_enum const Constants::CONST_ENUM = constant_enum::SOME_VALUE;
 
 std::experimental::optional<bool> const Constants::OPT_BOOL_CONSTANT = true;
 
@@ -41,6 +43,6 @@ ConstantRecord const Constants::OBJECT_CONSTANT = ConstantRecord(
     Constants::I32_CONSTANT /* some_integer */ ,
     Constants::STRING_CONSTANT /* some_string */ );
 
-bool const Constants::DUMMY = false;
+bool const Constants::DUMMY;
 
 }  // namespace testsuite

test-suite/generated-src/cpp/constants.hpp

@@ -4,6 +4,7 @@
 #pragma once
 
 #include "../../handwritten-src/cpp/optional.hpp"
+#include "constant_enum.hpp"
 #include "constant_record.hpp"
 #include <cstdint>
 #include <string>
@@ -15,24 +16,26 @@ namespace testsuite {
 struct Constants final {
 
     /** bool_constant has documentation. */
-    static bool const BOOL_CONSTANT;
+    static constexpr bool BOOL_CONSTANT = true;
 
-    static int8_t const I8_CONSTANT;
+    static constexpr int8_t I8_CONSTANT = 1;
 
-    static int16_t const I16_CONSTANT;
+    static constexpr int16_t I16_CONSTANT = 2;
 
-    static int32_t const I32_CONSTANT;
+    static constexpr int32_t I32_CONSTANT = 3;
 
-    static int64_t const I64_CONSTANT;
+    static constexpr int64_t I64_CONSTANT = 4;
 
-    static float const F32_CONSTANT;
+    static constexpr float F32_CONSTANT = 5.0f;
 
     /**
      * f64_constant has long documentation.
      * (Second line of multi-line documentation.
      *   Indented third line of multi-line documentation.)
      */
-    static double const F64_CONSTANT;
+    static constexpr double F64_CONSTANT = 5.0;
+
+    static constant_enum const CONST_ENUM;
 
     static std::experimental::optional<bool> const OPT_BOOL_CONSTANT;
 
@@ -65,7 +68,7 @@ struct Constants final {
      * No support for optional constant records
      * No support for constant binary, list, set, map
      */
-    static bool const DUMMY;
+    static constexpr bool DUMMY = false;
 };
 
 }  // namespace testsuite

test-suite/generated-src/cpp/constants_interface.cpp

@@ -2,23 +2,26 @@
 // This file generated by Djinni from constants.djinni
 
 #include "constants_interface.hpp"  // my header
+#include "constant_enum.hpp"
 #include "constant_record.hpp"
 
 namespace testsuite {
 
-bool const ConstantsInterface::BOOL_CONSTANT = true;
+bool const ConstantsInterface::BOOL_CONSTANT;
 
-int8_t const ConstantsInterface::I8_CONSTANT = 1;
+int8_t const ConstantsInterface::I8_CONSTANT;
 
-int16_t const ConstantsInterface::I16_CONSTANT = 2;
+int16_t const ConstantsInterface::I16_CONSTANT;
 
-int32_t const ConstantsInterface::I32_CONSTANT = 3;
+int32_t const ConstantsInterface::I32_CONSTANT;
 
-int64_t const ConstantsInterface::I64_CONSTANT = 4;
+int64_t const ConstantsInterface::I64_CONSTANT;
 
-float const ConstantsInterface::F32_CONSTANT = 5.0f;
+float const ConstantsInterface::F32_CONSTANT;
 
-double const ConstantsInterface::F64_CONSTANT = 5.0;
+double const ConstantsInterface::F64_CONSTANT;
+
+constant_enum const ConstantsInterface::CONST_ENUM = constant_enum::SOME_VALUE;
 
 std::experimental::optional<bool> const ConstantsInterface::OPT_BOOL_CONSTANT = true;
 

test-suite/generated-src/cpp/constants_interface.hpp

@@ -9,32 +9,35 @@
 
 namespace testsuite {
 
+enum class constant_enum;
 struct ConstantRecord;
 
 /** Interface containing constants */
 class ConstantsInterface {
 public:
     virtual ~ConstantsInterface() {}
 
-    static bool const BOOL_CONSTANT;
+    static constexpr bool BOOL_CONSTANT = true;
 
-    static int8_t const I8_CONSTANT;
+    static constexpr int8_t I8_CONSTANT = 1;
 
-    static int16_t const I16_CONSTANT;
+    static constexpr int16_t I16_CONSTANT = 2;
 
     /** i32_constant has documentation. */
-    static int32_t const I32_CONSTANT;
+    static constexpr int32_t I32_CONSTANT = 3;
 
     /**
      * i64_constant has long documentation.
      * (Second line of multi-line documentation.
      *   Indented third line of multi-line documentation.)
      */
-    static int64_t const I64_CONSTANT;
+    static constexpr int64_t I64_CONSTANT = 4;
 
-    static float const F32_CONSTANT;
+    static constexpr float F32_CONSTANT = 5.0f;
 
-    static double const F64_CONSTANT;
+    static constexpr double F64_CONSTANT = 5.0;
+
+    static constant_enum const CONST_ENUM;
 
     static std::experimental::optional<bool> const OPT_BOOL_CONSTANT;
 

test-suite/generated-src/java/com/dropbox/djinni/test/ConstantEnum.java

@@ -0,0 +1,14 @@
+// AUTOGENERATED FILE - DO NOT MODIFY!
+// This file generated by Djinni from constants.djinni
+
+package com.dropbox.djinni.test;
+
+import javax.annotation.CheckForNull;
+import javax.annotation.Nonnull;
+
+/** enum for use in constants */
+public enum ConstantEnum {
+    SOME_VALUE,
+    SOME_OTHER_VALUE,
+    ;
+}

test-suite/generated-src/java/com/dropbox/djinni/test/Constants.java

@@ -29,6 +29,9 @@ public class Constants {
      */
     public static final double F64_CONSTANT = 5.0;
 
+    @Nonnull
+    public static final ConstantEnum CONST_ENUM = ConstantEnum.SOME_VALUE;
+
     @CheckForNull
     public static final Boolean OPT_BOOL_CONSTANT = true;
 

test-suite/generated-src/java/com/dropbox/djinni/test/ConstantsInterface.java

@@ -29,6 +29,9 @@ public abstract class ConstantsInterface {
 
     public static final double F64_CONSTANT = 5.0;
 
+    @Nonnull
+    public static final ConstantEnum CONST_ENUM = ConstantEnum.SOME_VALUE;
+
     @CheckForNull
     public static final Boolean OPT_BOOL_CONSTANT = true;
 

test-suite/generated-src/jni/NativeConstantEnum.hpp

@@ -0,0 +1,26 @@
+// AUTOGENERATED FILE - DO NOT MODIFY!
+// This file generated by Djinni from constants.djinni
+
+#pragma once
+
+#include "constant_enum.hpp"
+#include "djinni_support.hpp"
+
+namespace djinni_generated {
+
+class NativeConstantEnum final : ::djinni::JniEnum {
+public:
+    using CppType = ::testsuite::constant_enum;
+    using JniType = jobject;
+
+    using Boxed = NativeConstantEnum;
+
+    static CppType toCpp(JNIEnv* jniEnv, JniType j) { return static_cast<CppType>(::djinni::JniClass<NativeConstantEnum>::get().ordinal(jniEnv, j)); }
+    static ::djinni::LocalRef<JniType> fromCpp(JNIEnv* jniEnv, CppType c) { return ::djinni::JniClass<NativeConstantEnum>::get().create(jniEnv, static_cast<jint>(c)); }
+
+private:
+    NativeConstantEnum() : JniEnum("com/dropbox/djinni/test/ConstantEnum") {}
+    friend ::djinni::JniClass<NativeConstantEnum>;
+};
+
+}  // namespace djinni_generated

test-suite/generated-src/jni/NativeConstantsInterface.cpp

@@ -3,6 +3,7 @@
 
 #include "NativeConstantsInterface.hpp"  // my header
 #include "Marshal.hpp"
+#include "NativeConstantEnum.hpp"
 #include "NativeConstantRecord.hpp"
 
 namespace djinni_generated {

test-suite/generated-src/objc/DBConstantEnum+Private.h

@@ -0,0 +1,6 @@
+// AUTOGENERATED FILE - DO NOT MODIFY!
+// This file generated by Djinni from constants.djinni
+
+#include "constant_enum.hpp"
+#import "DJIMarshal+Private.h"
+

test-suite/generated-src/objc/DBConstantEnum.h

@@ -0,0 +1,11 @@
+// AUTOGENERATED FILE - DO NOT MODIFY!
+// This file generated by Djinni from constants.djinni
+
+#import <Foundation/Foundation.h>
+
+/** enum for use in constants */
+typedef NS_ENUM(NSInteger, DBConstantEnum)
+{
+    DBConstantEnumSomeValue,
+    DBConstantEnumSomeOtherValue,
+};

test-suite/generated-src/objc/DBConstants+Private.mm

@@ -2,6 +2,7 @@
 // This file generated by Djinni from constants.djinni
 
 #import "DBConstants+Private.h"
+#import "DBConstantEnum+Private.h"
 #import "DBConstantRecord+Private.h"
 #import "DJIMarshal+Private.h"
 #include <cassert>