WebIDL binder: Added 'BindTo' extended attribute

This attribute can be used to change the C++ function that will be called. It can be used expose functions that have multiple overloads with the same number of parameters:

Example C++ code:

class BindToTest {
public:
  int test(const char*) { return 1; }
  int test(int) { return 2; }
};

IDL:

interface BindToTest {
  void BindToTest();
  [BindTo="test"] long testString([Const] DOMString arg);
  [BindTo="test"] long testInt(long arg);
};

Now the two overloaded functions can be called from JavaScript.

Author: jrouwe

test/webidl/post.js

@@ -317,5 +317,9 @@ if (isMemoryGrowthAllowed) {
   }
 }
 
+let bindTo = new TheModule.BindToTest();
+console.log('testString: ' + bindTo.testString('hello'));
+console.log('testInt: ' + bindTo.testInt(10));
+
 console.log('\ndone.')
 })();

test/webidl/test.h

@@ -242,3 +242,9 @@ class ArrayArgumentTest {
 private:
   const char* m_array;
 };
+
+class BindToTest {
+public:
+  int test(const char*) { return 1; }
+  int test(int) { return 2; }
+};

test/webidl/test.idl

@@ -212,3 +212,9 @@ interface JSArrayArgumentTest {
   boolean byteArrayTest([Const] byte[] arg);
   boolean domStringTest([Const] DOMString arg);
 };
+
+interface BindToTest {
+  void BindToTest();
+  [BindTo="test"] long testString([Const] DOMString arg);
+  [BindTo="test"] long testInt(long arg);
+};

test/webidl/test_ALL.out

@@ -114,3 +114,5 @@ Aborted(Assertion failed: [CHECK FAILED] StringUser::Print(anotherString:another
 123
 true
 true
+testString: 1
+testInt: 2

test/webidl/test_DEFAULT.out

@@ -113,5 +113,7 @@ Parent:42
 123
 true
 true
+testString: 1
+testInt: 2
 
 done.

test/webidl/test_FAST.out

@@ -113,5 +113,7 @@ Parent:42
 123
 true
 true
+testString: 1
+testInt: 2
 
 done.

third_party/WebIDL.py

@@ -3443,7 +3443,8 @@ def handleExtendedAttribute(self, attr):
               identifier == "Value" or
               identifier == "Operator" or
               identifier == "Const" or
-              identifier == "WebGLHandlesContextLoss"):
+              identifier == "WebGLHandlesContextLoss" or
+              identifier == "BindTo"):
             # Known attributes that we don't need to do anything with here
             pass
         else:

tools/webidl_binder.py

@@ -388,7 +388,8 @@ def type_to_cdec(raw):
 
 def render_function(class_name, func_name, sigs, return_type, non_pointer,
                     copy, operator, constructor, is_static, func_scope,
-                    call_content=None, const=False, array_attribute=False):
+                    call_content=None, const=False, array_attribute=False,
+                    bind_to=None):
   legacy_mode = CHECKS not in ['ALL', 'FAST']
   all_checks = CHECKS == 'ALL'
 
@@ -601,9 +602,10 @@ def make_call_args(i):
     elif call_content is not None:
       call = call_content
     else:
-      call = func_name + '(' + call_args + ')'
+      if not bind_to:
+        bind_to = func_name
+      call = bind_to + '(' + call_args + ')'
       if is_static:
-
         call = c_class_name + '::' + call
       else:
         call = 'self->' + call
@@ -771,7 +773,8 @@ def add_bounds_check_impl():
                     constructor,
                     is_static=m.isStatic(),
                     func_scope=m.parentScope.identifier.name,
-                    const=m.getExtendedAttribute('Const'))
+                    const=m.getExtendedAttribute('Const'),
+                    bind_to=(m.getExtendedAttribute('BindTo') or [None])[0])
     mid_js += ['\n']
     if constructor:
       mid_js += build_constructor(name)