addons.view: Add a focus tracker

mitmproxy/addons/view.py

@@ -3,9 +3,8 @@ The View:
 
 - Keeps track of a store of flows
 - Maintains a filtered, ordered view onto that list of flows
-- Exposes various operations on flows in the store - notably intercept and
-  resume
 - Exposes a number of signals so the view can be monitored
+- Has an associated class that tracks focus within the view
 """
 import collections
 import typing
@@ -94,6 +93,16 @@ class View(collections.Sequence):
                 self._view.add(f)
                 self.sig_add.send(self, flow=f)
 
+    def remove(self, f: flow.Flow):
+        """
+            Removes the flow from the underlying store and the view.
+        """
+        if f.id in self._store:
+            del self._store[f.id]
+            if f in self._view:
+                self._view.remove(f)
+                self.sig_remove.send(self, flow=f)
+
     def update(self, f: flow.Flow):
         """
             Updates a flow. If the flow is not in the state, it's ignored.
@@ -113,6 +122,13 @@ class View(collections.Sequence):
                     # The value was not in the view
                     pass
 
+    # Reflect some methods to the efficient underlying implementation
+    def bisect(self, f: flow.Flow) -> int:
+        return self._view.bisect(f)
+
+    def index(self, f: flow.Flow) -> int:
+        return self._view.index(f)
+
     # Event handlers
     def request(self, f):
         self.add(f)
@@ -128,3 +144,53 @@ class View(collections.Sequence):
 
     def response(self, f):
         self.update(f)
+
+
+class Focus:
+    """
+        Tracks a focus element within a View.
+    """
+    def __init__(self, v: View) -> None:
+        self.view = v
+        self._focusflow = None
+
+        self.focusflow = None
+        if len(self.view):
+            self.focusflow = self.view[0]
+        v.sig_add.connect(self._sig_add)
+        v.sig_remove.connect(self._sig_remove)
+        v.sig_refresh.connect(self._sig_refresh)
+
+    @property
+    def focusflow(self) -> typing.Optional[flow.Flow]:
+        return self._focusflow
+
+    @focusflow.setter
+    def focusflow(self, f: flow.Flow):
+        if f is not None and f not in self.view:
+            raise ValueError("Attempt to set focus to flow not in view")
+        self._focusflow = f
+
+    @property
+    def index(self) -> typing.Optional[int]:
+        if self.focusflow:
+            return self.view.index(self.focusflow)
+
+    def _sig_remove(self, view, flow):
+        if len(view) == 0:
+            self.focusflow = None
+        elif flow is self.focusflow:
+            idx = min(view.bisect(self.focusflow), len(view)-1)
+            self.focusflow = view[idx]
+
+    def _sig_refresh(self, view):
+        if len(view) == 0:
+            self.focusflow = None
+        else:
+            if self.focusflow not in view:
+                self.focusflow = view[0]
+
+    def _sig_add(self, view, flow):
+        # We only have to act if we don't have a focus element
+        if not self.focusflow:
+            self.focusflow = flow

test/mitmproxy/addons/test_view.py

@@ -161,3 +161,58 @@ def test_signals():
     clearrec()
     v.update(f)
     assert not any([rec_add, rec_update, rec_remove, rec_refresh])
+
+
+def test_focus():
+    # Special case - initialising with a view that already contains data
+    v = view.View()
+    v.add(tft())
+    f = view.Focus(v)
+    assert f.index is 0
+    assert f.focusflow is v[0]
+
+    # Start empty
+    v = view.View()
+    f = view.Focus(v)
+    assert f.index is None
+    assert f.focusflow is None
+
+    v.add(tft(start=1))
+    assert f.index == 0
+    assert f.focusflow is v[0]
+
+    v.add(tft(start=0))
+    assert f.index == 1
+    assert f.focusflow is v[1]
+
+    v.add(tft(start=2))
+    assert f.index == 1
+    assert f.focusflow is v[1]
+
+    v.remove(v[1])
+    assert f.index == 1
+    assert f.focusflow is v[1]
+
+    v.remove(v[1])
+    assert f.index == 0
+    assert f.focusflow is v[0]
+
+    v.remove(v[0])
+    assert f.index is None
+    assert f.focusflow is None
+
+    v.add(tft(method="get", start=0))
+    v.add(tft(method="get", start=1))
+    v.add(tft(method="put", start=2))
+    v.add(tft(method="get", start=3))
+
+    f.focusflow = v[2]
+    assert f.focusflow.request.method == "PUT"
+
+    filt = flowfilter.parse("~m get")
+    v.set_filter(filt)
+    assert f.index == 0
+
+    filt = flowfilter.parse("~m oink")
+    v.set_filter(filt)
+    assert f.index is None