Add indeterminate progress bar display when no total is given (ref #43)

lib/tty/progressbar.rb

@@ -33,9 +33,9 @@ class ProgressBar
 
     attr_reader :row
 
-    def_delegators :@configuration, :total, :width, :no_width, :complete,
-                   :incomplete, :head, :clear_head, :hide_cursor, :clear,
-                   :output, :frequency, :interval, :inset, :width=
+    def_delegators :@configuration, :total, :width, :complete, :incomplete,
+                   :head, :clear_head, :hide_cursor, :clear, :output,
+                   :frequency, :interval, :inset, :width=, :unknown
 
     def_delegators :@meter, :rate, :mean_rate
 
@@ -77,7 +77,7 @@ def self.display_columns(value)
     # @option options [Numeric] :width
     #   the maximum width for the bars display including
     #   all formatting options
-    # @option options [Boolean] :no_width
+    # @option options [Boolean] :indeterminate
     #   true when progression is unknown defaulting to false
     # @option options [Boolean] :clear
     #   whether or not to clear the progress line
@@ -117,9 +117,10 @@ def initialize(format, options = {})
     #
     # @api public
     def reset
-      @width             = 0 if no_width
+      @width             = 0 if indeterminate?
       @render_period     = frequency == 0 ? 0 : 1.0 / frequency
       @current           = 0
+      @unknown           = 0
       @last_render_time  = Time.now
       @last_render_width = 0
       @done              = false
@@ -131,6 +132,15 @@ def reset
       @meter.clear
     end
 
+    # Check if progress can be determinted or not
+    #
+    # @return [Boolean]
+    #
+    # @api public
+    def indeterminate?
+      total.nil?
+    end
+
     # Attach this bar to multi bar
     #
     # @param [TTY::ProgressBar::Multi] multibar
@@ -180,12 +190,16 @@ def advance(progress = 1, tokens = {})
         if progress.respond_to?(:to_hash)
           tokens, progress = progress, 1
         end
-        @start_at  = Time.now if @current.zero? && !@started
-        @current  += progress
-        @tokens    = tokens
+        @start_at = Time.now if @current.zero? && !@started
+        @current += progress
+        # When progress is unknown increase by 2% up to max 200%, after
+        # that reset back to 0%
+        @unknown += 2 if indeterminate?
+        @unknown = 0 if @unknown > 199
+        @tokens = tokens
         @meter.sample(Time.now, progress)
 
-        if !no_width && @current >= total
+        if !indeterminate? && @current >= total
           finish && return
         end
 
@@ -274,12 +288,20 @@ def ratio=(value)
 
     # Ratio of completed over total steps
     #
+    # When the total is unknown the progress ratio oscillates
+    # by going up from 0 to 1 and then down from 1 to 0 and
+    # up again to infinity.
+    #
     # @return [Float]
     #
     # @api public
     def ratio
       synchronize do
-        proportion = total > 0 ? (@current.to_f / total) : 0
+        proportion = if total
+                       total > 0 ? (@current.to_f / total) : 0
+                     else
+                       (@unknown > 100 ? 200 - @unknown : @unknown).to_f / 100
+                     end
         [[proportion, 0].max, 1].min
       end
     end
@@ -373,7 +395,7 @@ def resize(new_width = nil)
     # @api public
     def finish
       return if done?
-      @current = total unless no_width
+      @current = total unless indeterminate?
       render
       clear ? clear_line : write("\n", false)
     ensure

lib/tty/progressbar/configuration.rb

@@ -8,12 +8,12 @@ class Configuration
 
       attr_accessor :width
 
-      attr_accessor :no_width
-
       attr_accessor :incomplete
 
       attr_accessor :complete
 
+      attr_accessor :unknown
+
       attr_accessor :head
 
       attr_accessor :clear_head
@@ -33,9 +33,9 @@ class Configuration
       def initialize(options)
         self.total   = options[:total] if options[:total]
         @width       = options.fetch(:width) { total }
-        @no_width    = options.fetch(:no_width) { false }
         @incomplete  = options.fetch(:incomplete) { " " }
         @complete    = options.fetch(:complete) { "=" }
+        @unknown     = options.fetch(:unknown) { "<=>" }
         @head        = options.fetch(:head) { @complete || "=" }
         @clear_head  = options.fetch(:clear_head) { false }
         @hide_cursor = options.fetch(:hide_cursor) { false }

lib/tty/progressbar/formatter/bar.rb

@@ -34,7 +34,24 @@ def format(value)
         available_space = [0, ProgressBar.max_columns -
                               ProgressBar.display_columns(without_bar) -
                               @progress.inset].max
-        width = [@progress.width, available_space].min
+        width = [@progress.width.to_i, available_space].min
+
+        # When we don't know the total progress, use either user
+        # defined width or rely on terminal width detection
+        if @progress.indeterminate?
+          buffer = []
+          width = available_space if width.zero?
+          width -= @progress.unknown.size
+          complete = (width * @progress.ratio).round
+          incomplete = width - complete
+
+          buffer << " " * complete
+          buffer << @progress.unknown
+          buffer << " " * incomplete
+
+          return value.gsub(MATCHER, buffer.join)
+        end
+
         complete_bar_length    = (width * @progress.ratio).round
         complete_char_length   = ProgressBar.display_columns(@progress.complete)
         incomplete_char_length = ProgressBar.display_columns(@progress.incomplete)

spec/unit/formatter/bar_spec.rb

@@ -14,6 +14,21 @@
     ].join)
   end
 
+  it "animates unknown progress without total" do
+    progress = TTY::ProgressBar.new("[:bar]", output: output, total: nil, width: 5)
+    2.times { progress.advance }
+    progress.update(total: 5)
+    3.times { progress.advance }
+    output.rewind
+    expect(output.read).to eq([
+      "\e[1G[<=>  ]",
+      "\e[1G[<=>  ]",
+      "\e[1G[===  ]",
+      "\e[1G[==== ]",
+      "\e[1G[=====]\n"
+    ].join)
+  end
+
   it "animates colors correctly" do
     red = "\e[31m \e[0m"
     green = "\e[32m \e[0m"

spec/unit/indeterminate_spec.rb

@@ -0,0 +1,28 @@
+RSpec.describe TTY::ProgressBar, "indeterminate" do
+  let(:output) { StringIO.new("", "w+") }
+
+  it "animates indeterminate progress" do
+    progress = described_class.new("[:bar]", output: output, width: 10)
+    104.times { progress.advance }
+
+    output.rewind
+    expect(output.read).to eq([
+      "\e[1G[<=>       ]" * 3,
+      "\e[1G[ <=>      ]" * 7,
+      "\e[1G[  <=>     ]" * 7,
+      "\e[1G[   <=>    ]" * 7,
+      "\e[1G[    <=>   ]" * 8,
+      "\e[1G[     <=>  ]" * 7,
+      "\e[1G[      <=> ]" * 7,
+      "\e[1G[       <=>]" * 7,
+      "\e[1G[      <=> ]" * 7,
+      "\e[1G[     <=>  ]" * 7,
+      "\e[1G[    <=>   ]" * 8,
+      "\e[1G[   <=>    ]" * 7,
+      "\e[1G[  <=>     ]" * 7,
+      "\e[1G[ <=>      ]" * 7,
+      "\e[1G[<=>       ]" * 7,
+      "\e[1G[ <=>      ]"
+    ].join)
+  end
+end

spec/unit/pipeline_spec.rb

@@ -2,7 +2,7 @@
   subject(:pipeline) { described_class.new }
 
   it "decorates tokenized string with pipeline formatters" do
-    progress_bar = double(current: '3', total: '10')
+    progress_bar = double(current: '3', total: '10', indeterminate?: false)
     pipeline.use TTY::ProgressBar::CurrentFormatter.new(progress_bar)
     pipeline.use TTY::ProgressBar::TotalFormatter.new(progress_bar)
     tokenized = "[:current/:total]"

spec/unit/render_spec.rb

@@ -3,9 +3,7 @@
 
   it "pads out longer previous lines" do
     progress = TTY::ProgressBar.new ":current_byte" do |config|
-      config.no_width = true
-      config.output   = output
-      config.total    = 1_048_577
+      config.output = output
     end
 
     progress.advance(1)