Add Buffer.findMarker[s], which returns marker[s] matching attributes

spec/app/text-buffer-spec.coffee

@@ -954,6 +954,18 @@ describe 'Buffer', ->
         buffer.setMarkerHeadPosition(marker, [6, 2])
         expect(observeHandler).not.toHaveBeenCalled()
 
+    describe ".findMarkers(attributes)", ->
+      [marker1, marker2, marker3, marker4] = []
+
+      beforeEach ->
+        marker1 = buffer.markRange([[0, 0], [3, 0]], class: 'a')
+        marker2 = buffer.markRange([[0, 0], [5, 0]], class: 'a')
+        marker3 = buffer.markRange([[6, 0], [7, 0]], class: 'a')
+        marker4 = buffer.markRange([[9, 0], [10, 0]], class: 'b')
+
+      it "returns the markers matching the given attributes, sorted by the buffer location and size of their ranges", ->
+        expect(buffer.findMarkers(class: 'a')).toEqual [marker2, marker1, marker3]
+
     describe "marker destruction", ->
       marker = null
 

src/app/buffer-marker.coffee

@@ -13,7 +13,7 @@ class BufferMarker
   ###
   # Internal #
   ###
-  constructor: ({@id, @buffer, range, @invalidationStrategy, noTail, reverse}) ->
+  constructor: ({@id, @buffer, range, @invalidationStrategy, @attributes, noTail, reverse}) ->
     @invalidationStrategy ?= 'contains'
     @setRange(range, {noTail, reverse})
 
@@ -45,6 +45,14 @@ class BufferMarker
   isReversed: ->
     @tailPosition? and @headPosition.isLessThan(@tailPosition)
 
+  # Checks that the marker's attributes match the given attributes
+  #
+  # Returns a {Boolean}.
+  matchesAttributes: (queryAttributes) ->
+    for key, value of queryAttributes
+      return false unless _.isEqual(@attributes[key], value)
+    true
+
   # Public: Identifies if the marker's head position is equal to its tail.
   #
   # Returns a {Boolean}.

src/app/text-buffer.coffee

@@ -427,6 +427,19 @@ class Buffer
   getMarkers: ->
     _.values(@validMarkers)
 
+  # Public: Finds the first marker satisfying the given attributes
+  #
+  # Returns a {String} marker-identifier
+  findMarker: (attributes) ->
+
+  # Public: Finds all markers satisfying the given attributes
+  #
+  # Returns an {Array} of {String} marker-identifiers
+  findMarkers: (attributes) ->
+    markers = @getMarkers().filter (marker) -> marker.matchesAttributes(attributes)
+    markers.sort (a, b) -> a.getRange().compare(b.getRange())
+    _.pluck(markers, 'id')
+
   # Public: Retrieves the quantity of markers in a buffer.
   #
   # Returns a {Number}.
@@ -436,14 +449,23 @@ class Buffer
   # Public: Constructs a new marker at a given range.
   #
   # range - The marker {Range} (representing the distance between the head and tail)
-  # options - Options to pass to the {BufferMarker} constructor
+  # attributes - An optional hash of serializable attributes
+  #   Any attributes you pass will be associated with the marker and can be retrieved
+  #   or used in marker queries.
+  #   The following attribute keys reserved, and control the marker's initial range
+  #   reverse - if `true`, the marker is reversed; that is, its head precedes the tail
+  #   noTail - if `true`, the marker is created without a tail
   #
   # Returns a {Number} representing the new marker's ID.
-  markRange: (range, options={}) ->
+  markRange: (range, attributes={}) ->
+    optionKeys = ['invalidationStrategy', 'noTail', 'reverse']
+    options = _.pick(attributes, optionKeys)
+    attributes = _.omit(attributes, optionKeys)
     marker = new BufferMarker(_.defaults({
       id: (@nextMarkerId++).toString()
       buffer: this
       range
+      attributes
     }, options))
     @validMarkers[marker.id] = marker
     marker.id