Introduce View objects context property

Used to determine if an instance of the given class should
be closed or not when a project session is terminated.

data/core/commandview.lua

@@ -15,6 +15,8 @@ end
 
 local CommandView = DocView:extend()
 
+CommandView.context = "application"
+
 local max_suggestions = 10
 
 local noop = function() end

data/core/docview.lua

@@ -9,6 +9,7 @@ local View = require "core.view"
 
 local DocView = View:extend()
 
+DocView.context = "session"
 
 local function move_to_line_offset(dv, line, col, offset)
   local xo = dv.last_x_offset

data/core/logview.lua

@@ -5,6 +5,7 @@ local View = require "core.view"
 
 local LogView = View:extend()
 
+LogView.context = "session"
 
 function LogView:new()
   LogView.super.new(self)

data/core/rootview.lua

@@ -5,10 +5,8 @@ local style = require "core.style"
 local keymap = require "core.keymap"
 local Object = require "core.object"
 local View = require "core.view"
-local CommandView = require "core.commandview"
 local NagView = require "core.nagview"
 local DocView = require "core.docview"
-local LogView = require "core.logview"
 
 
 local EmptyView = View:extend()
@@ -602,8 +600,7 @@ function Node:close_all_docviews(keep_active)
     local i = 1
     while i <= #self.views do
       local view = self.views[i]
-      if (view:is(DocView) or view:is(LogView)) and not view:is(CommandView) and
-        (not keep_active or view ~= self.active_view) then
+      if view.context == "session" and (not keep_active or view ~= self.active_view) then
         table.remove(self.views, i)
         if view == node_active_view then
           lost_active_view = true

data/core/view.lua

@@ -7,6 +7,10 @@ local Object = require "core.object"
 
 local View = Object:extend()
 
+-- context can be "application" or "session". The instance of objects
+-- with context "session" will be closed when a project session is
+-- terminated. The context "application" is for functional UI elements.
+View.context = "application"
 
 function View:new()
   self.position = { x = 0, y = 0 }

data/plugins/projectsearch.lua

@@ -9,6 +9,7 @@ local View = require "core.view"
 
 local ResultsView = View:extend()
 
+ResultsView.context = "session"
 
 function ResultsView:new(text, fn)
   ResultsView.super.new(self)