tracer: Move more code to pathlib and f-strings

frida_tools/tracer.py

@@ -9,7 +9,6 @@
 import gzip
 import http
 import mimetypes
-import os
 import re
 import shlex
 import subprocess
@@ -275,17 +274,17 @@ def on_trace_events(self, raw_events) -> None:
                         self._last_event_tid = thread_id
                     self._print("%6d ms  %s%s%s%s" % (timestamp, attributes, indent, message, no_attributes))
 
-        def on_trace_handler_create(self, target: TraceTarget, handler: str, source: str) -> None:
+        def on_trace_handler_create(self, target: TraceTarget, handler: str, source: Path) -> None:
             self._register_handler(target, source)
             if self._quiet:
                 return
-            self._print('%s: Auto-generated handler at "%s"' % (target, source.replace("\\", "\\\\")))
+            self._print(f'{target}: Auto-generated handler at "{source}"')
 
-        def on_trace_handler_load(self, target: TraceTarget, handler: str, source: str) -> None:
+        def on_trace_handler_load(self, target: TraceTarget, handler: str, source: Path) -> None:
             self._register_handler(target, source)
             if self._quiet:
                 return
-            self._print('%s: Loaded handler at "%s"' % (target, source.replace("\\", "\\\\")))
+            self._print(f'{target}: Loaded handler at "{source}"')
 
         def _register_handler(self, target: TraceTarget, source: str) -> None:
             config = {"capture_backtraces": False}
@@ -599,9 +598,8 @@ def on_update(target, handler, source) -> None:
         )
 
         ui.on_trace_progress("initializing")
-        data_dir = os.path.dirname(__file__)
-        with codecs.open(os.path.join(data_dir, "tracer_agent.js"), "r", "utf-8") as f:
-            source = f.read()
+        data_dir = Path(__file__).parent
+        source = (data_dir / "tracer_agent.js").read_text(encoding="utf-8")
         script = session.create_script(name="tracer", source=source, runtime=runtime)
 
         self._script = script
@@ -832,7 +830,7 @@ def _create_stub_native_handler(self, target: TraceTarget, decorate: bool) -> st
 
     def _create_cstyle_logging_code(self, target: TraceTarget, decorate: bool) -> str:
         if decorate:
-            module_string = " [%s]" % os.path.basename(target.scope)
+            module_string = f" [{Path(target.scope).name}]"
         else:
             module_string = ""
 
@@ -865,7 +863,7 @@ def objc_arg(m):
 
     def _create_swift_logging_code(self, target: TraceTarget, decorate: bool) -> str:
         if decorate:
-            module_string = " [%s]" % os.path.basename(target.scope)
+            module_string = f" [{Path(target.scope).name}]"
         else:
             module_string = ""
         return "'%(name)s()%(module_string)s'" % {"name": target.name, "module_string": module_string}
@@ -1092,7 +1090,7 @@ def __init__(self, reactor: Reactor, decorate: bool) -> None:
         self._handler_by_file = {}
         self._changed_files = set()
         self._last_change_id = 0
-        self._repo_dir = os.path.join(os.getcwd(), "__handlers__")
+        self._repo_dir = Path.cwd() / "__handlers__"
         self._repo_monitors = {}
         self._decorate = decorate
 
@@ -1116,24 +1114,19 @@ def ensure_handler(self, target: TraceTarget) -> str:
 
         scope = target.scope
         if len(scope) > 0:
-            handler_file = os.path.join(
-                self._repo_dir, to_filename(os.path.basename(scope)), to_handler_filename(target.name)
-            )
+            handler_file = self._repo_dir / to_filename(Path(scope).name) / to_handler_filename(target.name)
         else:
-            handler_file = os.path.join(self._repo_dir, to_handler_filename(target.name))
+            handler_file = self._repo_dir / to_handler_filename(target.name)
 
-        if os.path.isfile(handler_file):
-            with codecs.open(handler_file, "r", "utf-8") as f:
-                handler = f.read()
+        if handler_file.is_file():
+            handler = self._load_handler(handler_file)
             self._notify_load(target, handler, handler_file)
 
         if handler is None:
             handler = self._create_stub_handler(target, self._decorate)
-            handler_dir = os.path.dirname(handler_file)
-            if not os.path.isdir(handler_dir):
-                os.makedirs(handler_dir)
-            with codecs.open(handler_file, "w", "utf-8") as f:
-                f.write(handler)
+            handler_dir = handler_file.parent
+            handler_dir.mkdir(parents=True, exist_ok=True)
+            handler_file.write_text(handler, encoding="utf-8")
             self._notify_create(target, handler, handler_file)
 
         entry = (target, handler, handler_file)
@@ -1144,28 +1137,33 @@ def ensure_handler(self, target: TraceTarget) -> str:
 
         return handler
 
+    def _load_handler(self, file: Path) -> None:
+        handler = file.read_text(encoding="utf-8")
+        return handler
+
     def update_handler(self, target: TraceTarget, handler: str) -> None:
         _, _, handler_file = self._handler_by_id.get(target.identifier)
         entry = (target, handler, handler_file)
         self._handler_by_id[target.identifier] = entry
         self._handler_by_file[handler_file] = entry
         self._notify_update(target, handler, handler_file)
 
-        Path(handler_file).write_text(handler, encoding="utf-8")
+        handler_file.write_text(handler, encoding="utf-8")
 
-    def _ensure_monitor(self, handler_file) -> None:
-        handler_dir = os.path.dirname(handler_file)
+    def _ensure_monitor(self, handler_file: Path) -> None:
+        handler_dir = handler_file.parent
         monitor = self._repo_monitors.get(handler_dir)
         if monitor is None:
-            monitor = frida.FileMonitor(handler_dir)
+            monitor = frida.FileMonitor(str(handler_dir))
             monitor.on("change", self._on_change)
             self._repo_monitors[handler_dir] = monitor
 
     def commit_handlers(self) -> None:
         for monitor in self._repo_monitors.values():
             monitor.enable()
 
-    def _on_change(self, changed_file, other_file, event_type) -> None:
+    def _on_change(self, raw_changed_file: str, other_file: str, event_type: str) -> None:
+        changed_file = Path(raw_changed_file)
         if changed_file not in self._handler_by_file or event_type == "changes-done-hint":
             return
         self._changed_files.add(changed_file)
@@ -1180,10 +1178,8 @@ def _sync_handlers(self, change_id) -> None:
         self._changed_files.clear()
         for changed_handler_file in changes:
             (target, old_handler, handler_file) = self._handler_by_file[changed_handler_file]
-            with codecs.open(handler_file, "r", "utf-8") as f:
-                new_handler = f.read()
-            changed = new_handler != old_handler
-            if changed:
+            new_handler = self._load_handler(handler_file)
+            if new_handler != old_handler:
                 entry = (target, new_handler, handler_file)
                 self._handler_by_id[target.identifier] = entry
                 self._handler_by_file[handler_file] = entry