[orca] Attempt to filter out terminal pager text-change noise

[Joanmarie Diggs <joanied src gnome org>]

commit 5afb51e5c87115fc3b2e13a4ea7de5611b24f483
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Mon Aug 22 15:18:04 2016 -0400

    Attempt to filter out terminal pager text-change noise
    
    We're not interested in pager deletion events, so processing these
    further and updating braille in response is a waste of time.

 src/orca/script_utilities.py |   25 +++++++++++++++++++++++++
 src/orca/scripts/default.py  |    5 +++++
 2 files changed, 30 insertions(+), 0 deletions(-)
---
diff --git a/src/orca/script_utilities.py b/src/orca/script_utilities.py
index f811ef4..389f0ca 100644
--- a/src/orca/script_utilities.py
+++ b/src/orca/script_utilities.py
@@ -4126,6 +4126,31 @@ class Utilities:
 
         return False
 
+    def treatEventAsTerminalNoise(self, event):
+        try:
+            role = event.source.getRole()
+        except:
+            msg = "ERROR: Exception getting role of %s" % event.source
+            debug.println(debug.LEVEL_INFO, msg, True)
+            return False
+
+        if role != pyatspi.ROLE_TERMINAL:
+            return False
+
+        if self.lastInputEventWasCommand():
+            return False
+
+        if event.type.startswith("object:text-changed:delete") and event.any_data.strip():
+            keyString, mods = self.lastKeyAndModifiers()
+            if keyString in ["Return", "Tab", "space", " "]:
+                return True
+            if mods & keybindings.ALT_MODIFIER_MASK:
+                return True
+            if len(event.any_data) > 1 and self.lastInputEventWasPrintableKey():
+                return True
+
+        return False
+
     def isPresentableTextChangedEventForLocusOfFocus(self, event):
         if not event.type.startswith("object:text-changed:") \
            and not event.type.startswith("object:text-attributes-changed"):
diff --git a/src/orca/scripts/default.py b/src/orca/scripts/default.py
index f111a4d..2c34ecf 100644
--- a/src/orca/scripts/default.py
+++ b/src/orca/scripts/default.py
@@ -2507,6 +2507,11 @@ class Script(script.Script):
         if not self.utilities.isPresentableTextChangedEventForLocusOfFocus(event):
             return
 
+        if self.utilities.treatEventAsTerminalNoise(event):
+            msg = "DEFAULT: Deletion is believed to be noise"
+            debug.println(debug.LEVEL_INFO, msg, True)
+            return
+
         self.utilities.handleUndoTextEvent(event)
 
         orca.setLocusOfFocus(event, event.source, False)