Add process filter feature

Src/args.swift

@@ -20,7 +20,8 @@ class ArgManager {
     var showpid = true
     var showpath = true
     var toFile: String?
-    let availableArgs = ["--nocolor", "--timeline", "--timestamps", "-o", "--standard", "--version", "--sources", "--nonetwork", "--nopid", "--nopath"]
+    var filterParent: String?
+    let availableArgs = ["--nocolor", "--timeline", "--timestamps", "-o", "--standard", "--version", "--sources", "--nonetwork", "--nopid", "--nopath", "--filter"]
 
     init(suppliedArgs: [String]) {
         setArgs(suppliedArgs)
@@ -57,6 +58,13 @@ class ArgManager {
                 } else {
                     toFile = "tree_output.txt"
                 }
+            } else if arg == "--filter" {
+                if args.count > x+1 && !availableArgs.contains(args[x+1]) {
+                    filterParent = args[x+1]
+                } else {
+                    print("--filter requires a PID or process name argument")
+                    exit(1)
+                }
             } else {
                 print("Unidentified argument " + arg)
                 exit(1)
@@ -75,6 +83,7 @@ class ArgManager {
         print("--nopath         Print process name only instead of full paths")
         print("--version        Print the TrueTree version number")
         print("-o <filename>    Output to file")
+        print("--filter <pid|name>  Show only the subtree rooted at the matching process")
         exit(0)
     }
 }

Src/main.swift

@@ -32,6 +32,19 @@ guard rootNode != nil else {
     exit(1)
 }
 
+// Helper: resolve the subtree root when --filter is supplied
+func resolveFilterRoot(from root: Node) -> Node {
+    guard let filter = argManager.filterParent else { return root }
+    if let pid = Int(filter), let found = root.search(pid: pid) {
+        return found
+    }
+    if let found = root.search(name: filter) {
+        return found
+    }
+    print("No process matching '\(filter)' was found in the tree.")
+    exit(1)
+}
+
 
 // If standard tree mode is active
 if argManager.standardMode {
@@ -42,7 +55,9 @@ if argManager.standardMode {
         // Assign this process as a child
         parentNode?.add(child: proc.node)
     }
-    rootNode?.printTree()
+
+    let printRoot = resolveFilterRoot(from: rootNode!)
+    printRoot.printTree()
     exit(0)
 }
 
@@ -93,5 +108,6 @@ for proc in pc.processes {
 }
 
 // print the launchd pid and all of it's children
-rootNode?.printTree()
+let printRoot = resolveFilterRoot(from: rootNode!)
+printRoot.printTree()
 

Src/node.swift

@@ -51,6 +51,30 @@ final class Node {
         }
         return nil
     }
+
+    func search(pid: Int) -> Node? {
+        if self.pid == pid {
+            return self
+        }
+        for child in children {
+            if let found = child.search(pid: pid) {
+                return found
+            }
+        }
+        return nil
+    }
+
+    func search(name: String) -> Node? {
+        if fileName.lowercased() == name.lowercased() || path.lowercased().contains(name.lowercased()) {
+            return self
+        }
+        for child in children {
+            if let found = child.search(name: name) {
+                return found
+            }
+        }
+        return nil
+    }
 }