Add support for -fvisibility=hidden and -fvisibility=default flags

CMakeLists.txt

@@ -6,6 +6,7 @@ include(GNUInstallDirs)
 
 set(SRC_SHARED
   "support-lib/djinni_common.hpp"
+  "support-lib/project_export.hpp"
   "support-lib/proxy_cache_interface.hpp"
   "support-lib/proxy_cache_impl.hpp"
 )

README.md

@@ -515,6 +515,23 @@ In order to do that, there are two steps needed:
 - deriving the records that should be parcelable with the keyword parcelable: `deriving(parcelable)`
 - run Djinni with the following flag `--java-implement-android-os-parcelable true`
 
+## Support for `-fvisibility=hidden` and `-fvisibility=default`
+
+You can pass `-fvisibility=hidden` or the `-fvisibility=default` flags to your compiler, Djinni handles both cases well.
+
+The symbols that are belonging to the public interfaces that are generated by Djinni are automatically defined to be visible symbols.
+To achieve this Djinni is marking the generated code with `PROJECT_EXPORT`.
+`PROJECT_EXPORT` is defined in `support-lib/project_export.hpp`.
+This macro is using the correct attribute specifier for the actual compiler. For more details, please check the macro definition in the `support-lib/project_export.hpp` header.
+
+Since the generated headers are including this `support-lib/project_export.hpp` header, you must distribute this header together with your library that is using Djinni.
+
+### Windows
+
+For Windows builds, you must define `BUILDING_DLL` based on your needs.
+You can define it as a compiler option like `-DBUILDING_DLL`.
+For more details, please check the macro definition in the `support-lib/project_export.hpp` header.
+
 ## Community Links
 
 * Join the discussion with other developers at the [Mobile C++ Slack Community](https://mobilecpp.herokuapp.com/)

src/source/CppGenerator.scala

@@ -59,6 +59,7 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
     val refs = new CppRefs(ident.name)
     val self = marshal.typename(ident, e)
 
+    refs.hpp.add("#include \"project_export.hpp\"")
     if (spec.cppEnumHashWorkaround) {
       refs.hpp.add("#include <functional>") // needed for std::hash
     }
@@ -101,7 +102,7 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
         wrapNamespace(w, "std",
           (w: IndentWriter) => {
             w.wl("template <>")
-            w.w(s"struct hash<$fqSelf>").bracedSemi {
+            w.w(s"struct PROJECT_EXPORT hash<$fqSelf>").bracedSemi {
               w.w(s"size_t operator()($fqSelf type) const").braced {
                 w.wl(s"return std::hash<$underlyingType>()(static_cast<$underlyingType>(type));")
               }
@@ -177,7 +178,7 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
       if (shouldConstexpr(c)){
         w.w(s"${marshal.fieldType(c.ty)} constexpr $selfName::${idCpp.const(c.ident)}")
       } else {
-        w.w(s"${marshal.fieldType(c.ty)} const $selfName::${idCpp.const(c.ident)} = ")
+        w.w(s"PROJECT_EXPORT ${marshal.fieldType(c.ty)} const $selfName::${idCpp.const(c.ident)} = ")
         writeCppConst(w, c.ty, c.value)
       }
       w.wl(";")
@@ -188,6 +189,7 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
     val refs = new CppRefs(ident.name)
     r.fields.foreach(f => refs.find(f.ty, false))
     r.consts.foreach(c => refs.find(c.ty, false))
+    refs.hpp.add("#include \"project_export.hpp\"")
     refs.hpp.add("#include <utility>") // Add for std::move
 
     val self = marshal.typename(ident, r)
@@ -202,13 +204,13 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
     // C++ Header
     def writeCppPrototype(w: IndentWriter) {
       if (r.ext.cpp) {
-        w.w(s"struct $self; // Requiring extended class")
+        w.w(s"struct PROJECT_EXPORT $self; // Requiring extended class")
         w.wl
         w.wl
       }
       writeDoc(w, doc)
       writeCppTypeParams(w, params)
-      w.w("struct " + actualSelf + cppFinal).bracedSemi {
+      w.w("struct PROJECT_EXPORT " + actualSelf + cppFinal).bracedSemi {
         generateHppConstants(w, r.consts)
         // Field definitions.
         for (f <- r.fields) {
@@ -218,18 +220,18 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
 
         if (r.derivingTypes.contains(DerivingType.Eq)) {
           w.wl
-          w.wl(s"friend bool operator==(const $actualSelf& lhs, const $actualSelf& rhs);")
-          w.wl(s"friend bool operator!=(const $actualSelf& lhs, const $actualSelf& rhs);")
+          w.wl(s"PROJECT_EXPORT friend bool operator==(const $actualSelf& lhs, const $actualSelf& rhs);")
+          w.wl(s"PROJECT_EXPORT friend bool operator!=(const $actualSelf& lhs, const $actualSelf& rhs);")
         }
         if (r.derivingTypes.contains(DerivingType.Ord)) {
           w.wl
-          w.wl(s"friend bool operator<(const $actualSelf& lhs, const $actualSelf& rhs);")
-          w.wl(s"friend bool operator>(const $actualSelf& lhs, const $actualSelf& rhs);")
+          w.wl(s"PROJECT_EXPORT friend bool operator<(const $actualSelf& lhs, const $actualSelf& rhs);")
+          w.wl(s"PROJECT_EXPORT friend bool operator>(const $actualSelf& lhs, const $actualSelf& rhs);")
         }
         if (r.derivingTypes.contains(DerivingType.Eq) && r.derivingTypes.contains(DerivingType.Ord)) {
           w.wl
-          w.wl(s"friend bool operator<=(const $actualSelf& lhs, const $actualSelf& rhs);")
-          w.wl(s"friend bool operator>=(const $actualSelf& lhs, const $actualSelf& rhs);")
+          w.wl(s"PROJECT_EXPORT friend bool operator<=(const $actualSelf& lhs, const $actualSelf& rhs);")
+          w.wl(s"PROJECT_EXPORT friend bool operator>=(const $actualSelf& lhs, const $actualSelf& rhs);")
         }
 
         // Constructor.
@@ -322,13 +324,15 @@ class CppGenerator(spec: Spec) extends Generator(spec) {
       refs.find(c.ty, true)
     })
 
+    refs.hpp.add("#include \"project_export.hpp\"")
+
     val self = marshal.typename(ident, i)
     val methodNamesInScope = i.methods.map(m => idCpp.method(m.ident))
 
     writeHppFile(ident, origin, refs.hpp, refs.hppFwds, w => {
       writeDoc(w, doc)
       writeCppTypeParams(w, typeParams)
-      w.w(s"class $self").bracedSemi {
+      w.w(s"class PROJECT_EXPORT $self").bracedSemi {
         w.wlOutdent("public:")
         // Destructor
         w.wl(s"virtual ~$self() {}")

src/source/ObjcGenerator.scala

@@ -98,12 +98,14 @@ class ObjcGenerator(spec: Spec) extends BaseObjcGenerator(spec) {
     writeObjcFile(marshal.headerName(ident), origin, refs.header, w => {
       for (c <- i.consts if marshal.canBeConstVariable(c)) {
         writeDoc(w, c.doc)
+        w.wl("__attribute__((visibility (\"default\")))")
         w.w(s"extern ")
         writeObjcConstVariableDecl(w, c, self)
         w.wl(s";")
       }
       w.wl
       writeDoc(w, doc)
+      w.wl("__attribute__((visibility (\"default\")))")
       if (i.ext.objc) w.wl(s"@protocol $self") else w.wl(s"@interface $self : NSObject")
       for (m <- i.methods) {
         w.wl
@@ -164,6 +166,7 @@ class ObjcGenerator(spec: Spec) extends BaseObjcGenerator(spec) {
     // Generate the header file for record
     writeObjcFile(marshal.headerName(objcName), origin, refs.header, w => {
       writeDoc(w, doc)
+      w.wl("__attribute__((visibility (\"default\")))")
       w.wl(s"@interface $self : NSObject")
 
       def writeInitializer(sign: String, prefix: String) {
@@ -198,6 +201,7 @@ class ObjcGenerator(spec: Spec) extends BaseObjcGenerator(spec) {
         w.wl
         for (c <- r.consts if marshal.canBeConstVariable(c)) {
           writeDoc(w, c.doc)
+          w.wl("__attribute__((visibility (\"default\")))")
           w.w(s"extern ")
           writeObjcConstVariableDecl(w, c, noBaseSelf);
           w.wl(s";")

src/source/ObjcppGenerator.scala

@@ -149,6 +149,7 @@ class ObjcppGenerator(spec: Spec) extends BaseObjcGenerator(spec) {
 
       if (i.ext.cpp) {
         w.wl
+        w.wl("__attribute__((visibility (\"default\")))")
         if (i.ext.objc)
           w.wl(s"@interface $objcSelf : NSObject<$self>")
         else

src/source/generator.scala

@@ -336,6 +336,7 @@ abstract class Generator(spec: Spec)
       w.wl("// This file generated by Djinni from " + origin)
       w.wl
       val myHeader = q(includePrefix + fileIdentStyle(name) + "." + spec.cppHeaderExt)
+      w.wl("#include \"project_export.hpp\"")
       w.wl(s"#include $myHeader  // my header")
       val myHeaderInclude = s"#include $myHeader"
       for (include <- includes if include != myHeaderInclude)

support-lib/project_export.hpp

@@ -0,0 +1,42 @@
+//
+// Copyright 2015 Dropbox, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+#ifndef PROJECT_EXPORT
+#    if defined _WIN32 || defined __CYGWIN__
+#        ifdef BUILDING_DLL
+#            ifdef __GNUC__
+#                define PROJECT_EXPORT __attribute__((dllexport))
+#            else
+#                define PROJECT_EXPORT __declspec(dllexport)
+#            endif
+#        else
+#            ifdef __GNUC__
+#                define PROJECT_EXPORT __attribute__((dllimport))
+#            else
+#                define PROJECT_EXPORT __declspec(dllimport)
+#            endif
+#        endif
+#        define PROJECT_LOCAL
+#    else
+#        if __GNUC__ >= 4
+#            define PROJECT_EXPORT __attribute__((visibility("default")))
+#            define PROJECT_LOCAL__attribute__ ((visibility("hidden")))
+#        else
+#            define PROJECT_EXPORT
+#            define PROJECT_LOCAL
+#        endif
+#    endif
+#endif

support-lib/support_lib.gyp

@@ -5,6 +5,7 @@
       "type": "static_library",
       "sources": [
         "djinni_common.hpp",
+        "project_export.hpp",
         "jni/djinni_support.cpp",
         "jni/djinni_support.hpp",
         "jni/Marshal.hpp",

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

@@ -3,13 +3,15 @@
 
 #pragma once
 
+#include "project_export.hpp"
+
 namespace testsuite {
 
 /**
  * Test for conflict of method name with an interface name.
  * See the comments about scopeSymbols in CppMarshal.scala for more info.
  */
-class Conflict {
+class PROJECT_EXPORT Conflict {
 public:
     virtual ~Conflict() {}
 };

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

@@ -3,13 +3,14 @@
 
 #pragma once
 
+#include "project_export.hpp"
 #include <memory>
 
 namespace testsuite {
 
 struct VarnameRecord;
 
-class VarnameInterface {
+class PROJECT_EXPORT VarnameInterface {
 public:
     virtual ~VarnameInterface() {}
 

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

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include "project_export.hpp"
 #include <cstdint>
 #include <utility>
 
@@ -13,7 +14,7 @@ namespace testsuite {
  * anticipate it to be used as a prefix/suffix.  Some name styles behave
  * badly when it is.  However this test case ensures we at least don't crash.
  */
-struct VarnameRecord final {
+struct PROJECT_EXPORT VarnameRecord final {
     int8_t _field_;
 
     VarnameRecord(int8_t _field__)

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

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include "project_export.hpp"
 #include <functional>
 
 namespace testsuite {
@@ -47,7 +48,7 @@ constexpr access_flags operator~(access_flags x) noexcept {
 namespace std {
 
 template <>
-struct hash<::testsuite::access_flags> {
+struct PROJECT_EXPORT hash<::testsuite::access_flags> {
     size_t operator()(::testsuite::access_flags type) const {
         return std::hash<unsigned>()(static_cast<unsigned>(type));
     }

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

@@ -1,6 +1,7 @@
 // AUTOGENERATED FILE - DO NOT MODIFY!
 // This file generated by Djinni from primtypes.djinni
 
+#include "project_export.hpp"
 #include "assorted_primitives.hpp"  // my header
 
 namespace testsuite {

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

@@ -4,12 +4,13 @@
 #pragma once
 
 #include "../../handwritten-src/cpp/optional.hpp"
+#include "project_export.hpp"
 #include <cstdint>
 #include <utility>
 
 namespace testsuite {
 
-struct AssortedPrimitives final {
+struct PROJECT_EXPORT AssortedPrimitives final {
     bool b;
     int8_t eight;
     int16_t sixteen;
@@ -25,8 +26,8 @@ struct AssortedPrimitives final {
     std::experimental::optional<float> o_fthirtytwo;
     std::experimental::optional<double> o_fsixtyfour;
 
-    friend bool operator==(const AssortedPrimitives& lhs, const AssortedPrimitives& rhs);
-    friend bool operator!=(const AssortedPrimitives& lhs, const AssortedPrimitives& rhs);
+    PROJECT_EXPORT friend bool operator==(const AssortedPrimitives& lhs, const AssortedPrimitives& rhs);
+    PROJECT_EXPORT friend bool operator!=(const AssortedPrimitives& lhs, const AssortedPrimitives& rhs);
 
     AssortedPrimitives(bool b_,
                        int8_t eight_,

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

@@ -4,6 +4,7 @@
 #pragma once
 
 #include "../../handwritten-src/cpp/optional.hpp"
+#include "project_export.hpp"
 #include <cstdint>
 #include <memory>
 #include <string>
@@ -14,7 +15,7 @@ namespace testsuite {
 struct ClientReturnedRecord;
 
 /** Client interface */
-class ClientInterface {
+class PROJECT_EXPORT ClientInterface {
 public:
     virtual ~ClientInterface() {}
 

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

@@ -4,14 +4,15 @@
 #pragma once
 
 #include "../../handwritten-src/cpp/optional.hpp"
+#include "project_export.hpp"
 #include <cstdint>
 #include <string>
 #include <utility>
 
 namespace testsuite {
 
 /** Record returned by a client */
-struct ClientReturnedRecord final {
+struct PROJECT_EXPORT ClientReturnedRecord final {
     int64_t record_id;
     std::string content;
     std::experimental::optional<std::string> misc;

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

@@ -3,6 +3,7 @@
 
 #pragma once
 
+#include "project_export.hpp"
 #include <functional>
 
 namespace testsuite {
@@ -27,7 +28,7 @@ enum class color : int {
 namespace std {
 
 template <>
-struct hash<::testsuite::color> {
+struct PROJECT_EXPORT hash<::testsuite::color> {
     size_t operator()(::testsuite::color type) const {
         return std::hash<int>()(static_cast<int>(type));
     }

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

@@ -3,14 +3,15 @@
 
 #pragma once
 
+#include "project_export.hpp"
 #include <memory>
 #include <unordered_set>
 
 namespace testsuite {
 
 class Conflict;
 
-class ConflictUser {
+class PROJECT_EXPORT ConflictUser {
 public:
     virtual ~ConflictUser() {}