[gjs] signals: addSignalMethods warns about overwriting

[Philip Chimento <pchimento src gnome org>]

commit 03558adf2e79606f5e6ca08018a3959d29f50c63
Author: Joe Shaw <joeshaw litl com>
Date:   Wed May 26 08:51:55 2010 -0400

    signals: addSignalMethods warns about overwriting
    
    Log a warning if addSignalMethods() replaces existing methods. Original
    patch by Joe Shaw, test added by Philip Chimento.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=619710

 Makefile-test.am                        |    5 ++++-
 installed-tests/scripts/testWarnings.sh |   25 +++++++++++++++++++++++++
 modules/signals.js                      |   17 +++++++++++++----
 3 files changed, 42 insertions(+), 5 deletions(-)
---
diff --git a/Makefile-test.am b/Makefile-test.am
index b9ac608..bcf6592 100644
--- a/Makefile-test.am
+++ b/Makefile-test.am
@@ -276,7 +276,10 @@ AM_TESTS_ENVIRONMENT =                                     \
        $(XVFB_START)                                   \
        $(NULL)
 
-simple_tests = installed-tests/scripts/testCommandLine.sh
+simple_tests =                                         \
+       installed-tests/scripts/testCommandLine.sh      \
+       installed-tests/scripts/testWarnings.sh         \
+       $(NULL)
 EXTRA_DIST += $(simple_tests)
 
 TESTS =                                \
diff --git a/installed-tests/scripts/testWarnings.sh b/installed-tests/scripts/testWarnings.sh
new file mode 100755
index 0000000..1cb1dc3
--- /dev/null
+++ b/installed-tests/scripts/testWarnings.sh
@@ -0,0 +1,25 @@
+#!/bin/sh
+
+if test $GJS_USE_UNINSTALLED_FILES -eq 1; then
+    gjs="$TOP_BUILDDIR"/gjs-console
+else
+    gjs=gjs-console
+fi
+
+total=0
+
+report () {
+    exit_code=$?
+    total=`expr $total + 1`
+    if test $exit_code -eq 0; then
+        echo "ok $total - $1"
+    else
+        echo "not ok $total - $1"
+    fi
+}
+
+"$gjs" -c 'imports.signals.addSignalMethods({connect: "foo"})' 2>&1 | \
+    grep -q 'addSignalMethods is replacing existing .* connect method'
+report "overwriting method with Signals.addSignalMethods() should warn"
+
+echo "1..$total"
diff --git a/modules/signals.js b/modules/signals.js
index 0905e53..2b0d03a 100644
--- a/modules/signals.js
+++ b/modules/signals.js
@@ -137,10 +137,19 @@ function _emit(name /* , arg1, arg2 */) {
     }
 }
 
+function _addSignalMethod(proto, functionName, func) {
+    if (proto[functionName] && proto[functionName] != func) {
+        log("WARNING: addSignalMethods is replacing existing " +
+            proto + " " + functionName + " method");
+    }
+
+    proto[functionName] = func;
+}
+
 function addSignalMethods(proto) {
-    proto.connect = _connect;
-    proto.disconnect = _disconnect;
-    proto.emit = _emit;
+    _addSignalMethod(proto, "connect", _connect);
+    _addSignalMethod(proto, "disconnect", _disconnect);
+    _addSignalMethod(proto, "emit", _emit);
     // this one is not in GObject, but useful
-    proto.disconnectAll = _disconnectAll;
+    _addSignalMethod(proto, "disconnectAll", _disconnectAll);
 }