[orca] Web: Prevent getting stuck/looping in offscreen single-char-lines text

[Joanmarie Diggs <joanied src gnome org>]

commit 5b039cef18d4cdd4916b84921b0d65e7f8a5797c
Author: Joanmarie Diggs <jdiggs igalia com>
Date:   Mon Feb 22 12:42:26 2021 +0100

    Web: Prevent getting stuck/looping in offscreen single-char-lines text
    
    When we search for the first valid caret position at/after a specified
    offset, we typically descend the element if the character at offset is
    an embedded object character. In the case of offscreen text which is
    exposed to us as one character per line, this can lead to getting stuck
    or looping because we always return a range of 0:length for the broken
    element.

 src/orca/scripts/web/script_utilities.py | 9 +++++++++
 1 file changed, 9 insertions(+)
---
diff --git a/src/orca/scripts/web/script_utilities.py b/src/orca/scripts/web/script_utilities.py
index 787a6c779..942ebd1b7 100644
--- a/src/orca/scripts/web/script_utilities.py
+++ b/src/orca/scripts/web/script_utilities.py
@@ -4869,6 +4869,9 @@ class Utilities(script_utilities.Utilities):
         self._contextPathsRolesAndNames[hash(parent)] = path, role, name
 
     def findFirstCaretContext(self, obj, offset):
+        msg = "WEB: Looking for first caret context for %s, %i" % (obj, offset)
+        debug.println(debug.LEVEL_INFO, msg, True)
+
         try:
             role = obj.getRole()
         except:
@@ -4918,6 +4921,12 @@ class Utilities(script_utilities.Utilities):
                 debug.println(debug.LEVEL_INFO, msg, True)
                 return obj, offset
 
+            # Descending an element that we're treating as a whole can lead to looping/getting stuck.
+            if self.elementLinesAreSingleChars(obj):
+                msg = "WEB: EOC in single-char-lines element. Returning %s, %i unchanged." % (obj, offset)
+                debug.println(debug.LEVEL_INFO, msg, True)
+                return obj, offset
+
         child = self.getChildAtOffset(obj, offset)
         if not child:
             msg = "WEB: Child at offset is null. Returning %s, %i unchanged." % (obj, offset)