build: fix windows build

Be very careful with forward declarations, MSVC is quite picky and
rather stupid about it.

Fixes nodejs#5810.

src/node.cc

@@ -740,7 +740,7 @@ Local<Value> ErrnoException(int errorno,
                             const char *path) {
   Local<Value> e;
   Local<String> estring = String::NewSymbol(errno_string(errorno));
-  if (!msg[0]) {
+  if (msg == NULL || msg[0] == '\0') {
     msg = strerror(errorno);
   }
   Local<String> message = String::NewSymbol(msg);

src/node.h

@@ -66,6 +66,36 @@
 
 #include "node_object_wrap.h"
 
+// Forward-declare these functions now to stop MSVS from becoming
+// terminally confused when it's done in node_internals.h
+namespace node {
+
+NODE_EXTERN v8::Local<v8::Value> ErrnoException(int errorno,
+                                                const char* syscall = NULL,
+                                                const char* message = NULL,
+                                                const char* path = NULL);
+NODE_EXTERN v8::Local<v8::Value> UVException(int errorno,
+                                             const char* syscall = NULL,
+                                             const char* message = NULL,
+                                             const char* path = NULL);
+NODE_EXTERN v8::Handle<v8::Value> MakeCallback(
+    const v8::Handle<v8::Object> recv,
+    const char* method,
+    int argc,
+    v8::Handle<v8::Value>* argv);
+NODE_EXTERN v8::Handle<v8::Value> MakeCallback(
+    const v8::Handle<v8::Object> object,
+    const v8::Handle<v8::String> symbol,
+    int argc,
+    v8::Handle<v8::Value>* argv);
+NODE_EXTERN v8::Handle<v8::Value> MakeCallback(
+    const v8::Handle<v8::Object> object,
+    const v8::Handle<v8::Function> callback,
+    int argc,
+    v8::Handle<v8::Value>* argv);
+
+}  // namespace node
+
 #if NODE_WANT_INTERNALS
 # include "node_internals.h"
 #endif
@@ -147,16 +177,6 @@ NODE_EXTERN ssize_t DecodeWrite(char *buf,
 v8::Local<v8::Object> BuildStatsObject(const uv_stat_t* s);
 
 
-NODE_EXTERN v8::Local<v8::Value> ErrnoException(int errorno,
-                                                const char *syscall = NULL,
-                                                const char *msg = "",
-                                                const char *path = NULL);
-
-NODE_EXTERN v8::Local<v8::Value> UVException(int errorno,
-                                             const char *syscall = NULL,
-                                             const char *msg     = NULL,
-                                             const char *path    = NULL);
-
 #ifdef _WIN32
 NODE_EXTERN v8::Local<v8::Value> WinapiErrnoException(int errorno,
     const char *syscall = NULL,  const char *msg = "",
@@ -217,23 +237,6 @@ node_module_struct* get_builtin_module(const char *name);
 NODE_EXTERN void AtExit(void (*cb)(void* arg), void* arg = 0);
 
 NODE_EXTERN void SetErrno(uv_err_t err);
-NODE_EXTERN v8::Handle<v8::Value>
-MakeCallback(const v8::Handle<v8::Object> object,
-             const char* method,
-             int argc,
-             v8::Handle<v8::Value> argv[]);
-
-NODE_EXTERN v8::Handle<v8::Value>
-MakeCallback(const v8::Handle<v8::Object> object,
-             const v8::Handle<v8::String> symbol,
-             int argc,
-             v8::Handle<v8::Value> argv[]);
-
-NODE_EXTERN v8::Handle<v8::Value>
-MakeCallback(const v8::Handle<v8::Object> object,
-             const v8::Handle<v8::Function> callback,
-             int argc,
-             v8::Handle<v8::Value> argv[]);
 
 }  // namespace node
 

src/node_buffer.cc

@@ -21,7 +21,6 @@
 
 
 #include "node.h"
-#include "node_internals.h"
 #include "node_buffer.h"
 #include "smalloc.h"
 #include "string_bytes.h"

src/node_internals.h

@@ -29,6 +29,21 @@
 
 namespace node {
 
+// Forward declarations from node_buffer.h.  We can't include node_buffer.h
+// in this file because:
+//
+// a) we're included early on in node.h, and
+// b) node_buffer.h depends on the definition of the |encoding| enum that's
+//    defined further down in node.h...
+namespace Buffer {
+
+NODE_EXTERN char* Data(v8::Handle<v8::Value>);
+NODE_EXTERN char* Data(v8::Handle<v8::Object>);
+NODE_EXTERN size_t Length(v8::Handle<v8::Value>);
+NODE_EXTERN size_t Length(v8::Handle<v8::Object>);
+
+} // namespace Buffer
+
 // Defined in node.cc
 extern v8::Isolate* node_isolate;
 
@@ -177,21 +192,13 @@ inline static void ThrowErrnoException(int errorno,
                                        const char* syscall = NULL,
                                        const char* message = NULL,
                                        const char* path = NULL) {
-  NODE_EXTERN v8::Local<v8::Value> ErrnoException(int errorno,
-                                                  const char* syscall = NULL,
-                                                  const char* message = NULL,
-                                                  const char* path = NULL);
   v8::ThrowException(ErrnoException(errorno, syscall, message, path));
 }
 
 inline static void ThrowUVException(int errorno,
                                     const char* syscall = NULL,
                                     const char* message = NULL,
                                     const char* path = NULL) {
-  NODE_EXTERN v8::Local<v8::Value> UVException(int errorno,
-                                               const char* syscall = NULL,
-                                               const char* message = NULL,
-                                               const char* path = NULL);
   v8::ThrowException(UVException(errorno, syscall, message, path));
 }
 
@@ -309,23 +316,6 @@ inline void Cached<v8::Value>::operator=(v8::Handle<v8::Value> that) {
   CachedBase<v8::Value>::operator=(that);
 }
 
-// Forward declarations, see node.h
-NODE_EXTERN v8::Handle<v8::Value> MakeCallback(
-    const v8::Handle<v8::Object> recv,
-    const char* method,
-    int argc,
-    v8::Handle<v8::Value>* argv);
-NODE_EXTERN v8::Handle<v8::Value> MakeCallback(
-    const v8::Handle<v8::Object> object,
-    const v8::Handle<v8::String> symbol,
-    int argc,
-    v8::Handle<v8::Value>* argv);
-NODE_EXTERN v8::Handle<v8::Value> MakeCallback(
-    const v8::Handle<v8::Object> object,
-    const v8::Handle<v8::Function> callback,
-    int argc,
-    v8::Handle<v8::Value>* argv);
-
 template <typename TypeName>
 v8::Handle<v8::Value> MakeCallback(
     const v8::Persistent<v8::Object>& recv,
@@ -364,15 +354,11 @@ namespace Buffer {
 
 template <typename TypeName>
 inline char* Data(v8::Persistent<TypeName>& val) {
-  NODE_EXTERN char* Data(v8::Handle<v8::Value>);
-  NODE_EXTERN char* Data(v8::Handle<v8::Object>);
   return Data(PersistentToLocal(val));
 }
 
 template <typename TypeName>
 inline size_t Length(v8::Persistent<TypeName>& val) {
-  NODE_EXTERN size_t Length(v8::Handle<v8::Value>);
-  NODE_EXTERN size_t Length(v8::Handle<v8::Object>);
   return Length(PersistentToLocal(val));
 }
 

src/req_wrap.h

@@ -23,7 +23,6 @@
 #define REQ_WRAP_H_
 
 #include "queue.h"
-#include "node_internals.h"
 
 namespace node {