Bug 239460 - Specify types for XPIDL consts in C++, r=xpcom-reviewers…

…,mccr8

Before this change, all XPIDL constants were declared using an anonymous
`enum` rather than using a static constant. This change makes the
generated code more consistent with what is done in languages like Rust.

Some small changes were needed due to signed/unsigned comparison
warnings which were previously silent.

Differential Revision: https://phabricator.services.mozilla.com/D143090

netwerk/cookie/nsICookie.idl

@@ -15,9 +15,9 @@ typedef long nsCookiePolicy;
 
 [builtinclass, scriptable, uuid(adf0db5e-211e-45a3-be14-4486ac430a58)]
 interface nsICookie : nsISupports {
-    const uint32_t SAMESITE_NONE   = 0;
-    const uint32_t SAMESITE_LAX    = 1;
-    const uint32_t SAMESITE_STRICT = 2;
+    const int32_t SAMESITE_NONE   = 0;
+    const int32_t SAMESITE_LAX    = 1;
+    const int32_t SAMESITE_STRICT = 2;
 
     /**
      * the name of the cookie

xpcom/idl-parser/xpidl/header.py

@@ -495,22 +495,16 @@ def record_name(name):
             record_name(methodNativeName(m))
 
     def write_const_decls(g):
-        fd.write("  enum {\n")
-        enums = []
         for c in g:
             printComments(fd, c.doccomments, "  ")
-            basetype = c.basetype
-            value = c.getValue()
-            enums.append(
-                "    %(name)s = %(value)s%(signed)s"
+            fd.write(
+                "  static constexpr %(type)s %(name)s = %(value)s;\n"
                 % {
+                    "type": c.realtype.nativeType("in"),
                     "name": c.name,
-                    "value": value,
-                    "signed": (not basetype.signed) and "U" or "",
+                    "value": c.getValue(),
                 }
             )
-        fd.write(",\n".join(enums))
-        fd.write("\n  };\n\n")
 
     def write_cenum_decl(b):
         fd.write("  enum %s : uint%d_t {\n" % (b.basename, b.width))

xpcom/system/nsIXULRuntime.idl

@@ -272,7 +272,7 @@ interface nsIXULRuntime : nsISupports
    * The current e10s-multi experiment number. Set dom.ipc.multiOptOut to (at
    * least) this to disable it until the next experiment.
    */
-  const uint32_t E10S_MULTI_EXPERIMENT = 1;
+  const int32_t E10S_MULTI_EXPERIMENT = 1;
 
   /**
    * If true, the accessibility service is running.

xpfe/appshell/AppWindow.cpp

@@ -1465,8 +1465,10 @@ bool AppWindow::UpdateWindowStateFromMiscXULAttributes() {
   if (!stateString.IsEmpty()) {
     nsresult errorCode;
     int32_t zLevel = stateString.ToInteger(&errorCode);
-    if (NS_SUCCEEDED(errorCode) && zLevel >= lowestZ && zLevel <= highestZ)
+    if (NS_SUCCEEDED(errorCode) && zLevel >= int32_t(lowestZ) &&
+        zLevel <= int32_t(highestZ)) {
       SetZLevel(zLevel);
+    }
   }
 
   return gotState;