Improve trusted-prune-inbound-object scriptlet

Trap incoming argument only if it matches the properties to
prune and matches. If there is no match, the inbound object
is passed through untouched.

assets/resources/scriptlets.js

@@ -630,6 +630,7 @@ builtinScriptlets.push({
     fn: objectPruneFn,
     dependencies: [
         'matches-stack-trace.fn',
+        'object-find-owner.fn',
         'safe-self.fn',
         'should-log.fn',
     ],
@@ -662,8 +663,50 @@ function objectPruneFn(
             return;
         }
     }
-    if ( objectPruneFn.findOwner === undefined ) {
+    if ( objectPruneFn.mustProcess === undefined ) {
-        objectPruneFn.findOwner = (root, path, prune = false) => {
+        objectPruneFn.mustProcess = (root, needlePaths) => {
+            for ( const needlePath of needlePaths ) {
+                if ( objectFindOwnerFn(root, needlePath) === false ) {
+                    return false;
+                }
+            }
+            return true;
+        };
+        objectPruneFn.logJson = (json, msg, reNeedle) => {
+            if ( reNeedle.test(json) === false ) { return; }
+            safeSelf().uboLog(`objectPrune()`, msg, location.hostname, json);
+        };
+    }
+    const jsonBefore = logLevel ? safe.JSON_stringify(obj, null, 2) : '';
+    if ( logLevel === true || logLevel === 'all' ) {
+        objectPruneFn.logJson(jsonBefore, `prune:"${rawPrunePaths}" log:"${logLevel}"`, reLogNeedle);
+    }
+    if ( prunePaths.length === 0 ) { return; }
+    let outcome = 'nomatch';
+    if ( objectPruneFn.mustProcess(obj, needlePaths) ) {
+        for ( const path of prunePaths ) {
+            if ( objectFindOwnerFn(obj, path, true) ) {
+                outcome = 'match';
+            }
+        }
+    }
+    if ( logLevel === outcome ) {
+        objectPruneFn.logJson(jsonBefore, `prune:"${rawPrunePaths}" log:"${logLevel}"`, reLogNeedle);
+    }
+    if ( outcome === 'match' ) { return obj; }
+}
+
+/******************************************************************************/
+
+builtinScriptlets.push({
+    name: 'object-find-owner.fn',
+    fn: objectFindOwnerFn,
+});
+function objectFindOwnerFn(
+    root,
+    path,
+    prune = false
+) {
     let owner = root;
     let chain = path;
     for (;;) {
@@ -694,7 +737,7 @@ function objectPruneFn(
             const next = chain.slice(pos + 1);
             let found = false;
             for ( const key of Object.keys(owner) ) {
-                        found = objectPruneFn.findOwner(owner[key], next, prune) || found;
+                found = objectFindOwnerFn(owner[key], next, prune) || found;
             }
             return found;
         }
@@ -702,37 +745,7 @@ function objectPruneFn(
         owner = owner[prop];
         chain = chain.slice(pos + 1);
     }
-        };
-        objectPruneFn.mustProcess = (root, needlePaths) => {
-            for ( const needlePath of needlePaths ) {
-                if ( objectPruneFn.findOwner(root, needlePath) === false ) {
-                    return false;
-                }
-            }
     return true;
-        };
-        objectPruneFn.logJson = (json, msg, reNeedle) => {
-            if ( reNeedle.test(json) === false ) { return; }
-            safeSelf().uboLog(`objectPrune()`, msg, location.hostname, json);
-        };
-    }
-    const jsonBefore = logLevel ? safe.JSON_stringify(obj, null, 2) : '';
-    if ( logLevel === true || logLevel === 'all' ) {
-        objectPruneFn.logJson(jsonBefore, `prune:"${rawPrunePaths}" log:"${logLevel}"`, reLogNeedle);
-    }
-    if ( prunePaths.length === 0 ) { return; }
-    let outcome = 'nomatch';
-    if ( objectPruneFn.mustProcess(obj, needlePaths) ) {
-        for ( const path of prunePaths ) {
-            if ( objectPruneFn.findOwner(obj, path, true) ) {
-                outcome = 'match';
-            }
-        }
-    }
-    if ( logLevel === outcome ) {
-        objectPruneFn.logJson(jsonBefore, `prune:"${rawPrunePaths}" log:"${logLevel}"`, reLogNeedle);
-    }
-    if ( outcome === 'match' ) { return obj; }
 }
 
 /******************************************************************************/
@@ -4055,6 +4068,7 @@ builtinScriptlets.push({
     requiresTrust: true,
     fn: trustedPruneInboundObject,
     dependencies: [
+        'object-find-owner.fn',
         'object-prune.fn',
         'safe-self.fn',
     ],
@@ -4081,15 +4095,36 @@ function trustedPruneInboundObject(
     if ( argIndex < 1 ) { return; }
     const safe = safeSelf();
     const extraArgs = safe.getExtraArgs(Array.from(arguments), 4);
+    const needlePaths = [];
+    if ( rawPrunePaths !== '' ) {
+        needlePaths.push(...rawPrunePaths.split(/ +/));
+    }
+    if ( rawNeedlePaths !== '' ) {
+        needlePaths.push(...rawNeedlePaths.split(/ +/));
+    }
+    const mustProcess = root => {
+        for ( const needlePath of needlePaths ) {
+            if ( objectFindOwnerFn(root, needlePath) === false ) {
+                return false;
+            }
+        }
+        return true;
+    };
     context[prop] = new Proxy(context[prop], {
         apply: function(target, thisArg, args) {
             const targetArg = argIndex <= args.length
                 ? args[argIndex-1]
                 : undefined;
-            if ( targetArg instanceof Object ) {
+            if ( targetArg instanceof Object && mustProcess(targetArg) ) {
-                const objBefore = extraArgs.dontOverwrite
+                let objBefore = targetArg;
-                    ? safe.JSON_parse(safe.JSON_stringify(targetArg))
+                if ( extraArgs.dontOverwrite ) {
-                    : targetArg;
+                    try {
+                        objBefore = safe.JSON_parse(safe.JSON_stringify(targetArg));
+                    } catch(_) {
+                        objBefore = undefined;
+                    }
+                }
+                if ( objBefore !== undefined ) {
                     const objAfter = objectPruneFn(
                         objBefore,
                         rawPrunePaths,
@@ -4099,6 +4134,7 @@ function trustedPruneInboundObject(
                     );
                     args[argIndex-1] = objAfter || objBefore;
                 }
+            }
             return Reflect.apply(target, thisArg, args);
         },
     });