[Console][ProgressBar] Developer experience

- Create getProgress/setProgress methods to replace getStep/setCurrent
 - ProgressBar::setCurrent should auto-start the ProgressBar.
 - You should be able to pass max to start
 - getStepWidth is internal information that should not be public
 - when verbosity set to quiet, the progress bar does not even need to
   execute all the logic to generate output that is then thrown away

src/Symfony/Component/Console/Helper/ProgressBar.php

@@ -55,6 +55,10 @@ class ProgressBar
      */
     public function __construct(OutputInterface $output, $max = 0)
     {
+        if (!is_integer($max) || $max < 0) {
+            throw new \InvalidArgumentException('Max steps should be a positive integer, 0 or null. Got "%s".', $max);
+        }
+
         // Disabling output when it does not support ANSI codes as it would result in a broken display anyway.
         $this->output = $output->isDecorated() ? $output : new NullOutput();
         $this->max = (int) $max;
@@ -69,6 +73,12 @@ class ProgressBar
         }
 
         $this->setFormat($this->determineBestFormat());
+
+        $this->startTime = time();
+        $this->step = 0;
+        $this->percent = 0;
+        $this->lastMessagesLength = 0;
+        $this->barCharOriginal = '';
     }
 
     /**
@@ -170,9 +180,21 @@ class ProgressBar
     /**
      * Gets the progress bar step.
      *
+     * @deprecated since 2.6, to be removed in 3.0. Use {@link getCurrent()} instead.
+     *
      * @return int     The progress bar step
      */
     public function getStep()
+    {
+        return $this->getCurrent();
+    }
+
+    /**
+     * Gets the progress bar step.
+     *
+     * @return int The progress bar step
+     */
+    public function getCurrent()
     {
         return $this->step;
     }
@@ -180,6 +202,8 @@ class ProgressBar
     /**
      * Gets the progress bar step width.
      *
+     * @deprecated since 2.6, it will be marked private from 3.0.
+     *
      * @return int     The progress bar step width
      */
     public function getStepWidth()
@@ -308,14 +332,15 @@ class ProgressBar
 
     /**
      * Starts the progress output.
+     *
+     * @param int    $max Maximum Step (0 if unknown)
      */
-    public function start()
+    public function start($max = 0)
     {
-        $this->startTime = time();
+        if (0 !== $max) {
-        $this->step = 0;
+            $this->max = $max;
-        $this->percent = 0;
+            $this->stepWidth = $this->max > 0 ? Helper::strlen($this->max) : 4;
-        $this->lastMessagesLength = 0;
+        }
-        $this->barCharOriginal = '';
 
         if (!$this->max) {
             $this->barCharOriginal = $this->barChar;
@@ -346,10 +371,6 @@ class ProgressBar
      */
     public function setCurrent($step)
     {
-        if (null === $this->startTime) {
-            throw new \LogicException('You must start the progress bar before calling setCurrent().');
-        }
-
         $step = (int) $step;
         if ($step < $this->step) {
             throw new \LogicException('You can\'t regress the progress bar.');
@@ -373,10 +394,6 @@ class ProgressBar
      */
     public function finish()
     {
-        if (null === $this->startTime) {
-            throw new \LogicException('You must start the progress bar before calling finish().');
-        }
-
         if (!$this->max) {
             $this->barChar = $this->barCharOriginal;
             $this->max = $this->step;
@@ -397,8 +414,8 @@ class ProgressBar
      */
     public function display()
     {
-        if (null === $this->startTime) {
+        if (OutputInterface::VERBOSITY_QUIET === $this->output->getVerbosity()) {
-            throw new \LogicException('You must start the progress bar before calling display().');
+            return;
         }
 
         // these 3 variables can be removed in favor of using $this in the closure when support for PHP 5.3 will be dropped.

src/Symfony/Component/Console/Tests/Helper/ProgressBarTest.php

@@ -19,6 +19,14 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
 {
     protected $lastMessagesLength;
 
+    /**
+     * @expectedException InvalidArgumentException
+     */
+    public function testInitializeWithNegativeMax()
+    {
+        $bar = new ProgressBar($output = $this->getOutputStream(), -1);
+    }
+
     public function testAdvance()
     {
         $bar = new ProgressBar($output = $this->getOutputStream());
@@ -82,6 +90,42 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
         );
     }
 
+    public function testDisplayWithoutStart()
+    {
+        $bar = new ProgressBar($output = $this->getOutputStream(), 50);
+        $bar->display();
+
+        rewind($output->getStream());
+        $this->assertEquals(
+            $this->generateOutput('  0/50 [>---------------------------]   0%'),
+            stream_get_contents($output->getStream())
+        );
+    }
+
+    public function testDisplayWithQuietVerbosity()
+    {
+        $bar = new ProgressBar($output = $this->getOutputStream(true, StreamOutput::VERBOSITY_QUIET), 50);
+        $bar->display();
+
+        rewind($output->getStream());
+        $this->assertEquals(
+            '',
+            stream_get_contents($output->getStream())
+        );
+    }
+
+    public function testFinishWithoutStart()
+    {
+        $bar = new ProgressBar($output = $this->getOutputStream(), 50);
+        $bar->finish();
+
+        rewind($output->getStream());
+        $this->assertEquals(
+            $this->generateOutput(' 50/50 [============================] 100%'),
+            stream_get_contents($output->getStream())
+        );
+    }
+
     public function testPercent()
     {
         $bar = new ProgressBar($output = $this->getOutputStream(), 50);
@@ -122,6 +166,23 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
         );
     }
 
+    public function testStartWithMax()
+    {
+        $bar = new ProgressBar($output = $this->getOutputStream());
+        $bar->setFormat('%current%/%max% [%bar%]');
+        $bar->start(50);
+        $bar->display();
+        $bar->advance();
+
+        rewind($output->getStream());
+        $this->assertEquals(
+            $this->generateOutput(' 0/50 [>---------------------------]').
+            $this->generateOutput(' 0/50 [>---------------------------]').
+            $this->generateOutput(' 1/50 [>---------------------------]'),
+            stream_get_contents($output->getStream())
+        );
+    }
+
     public function testSetCurrentProgress()
     {
         $bar = new ProgressBar($output = $this->getOutputStream(), 50);
@@ -143,13 +204,12 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
     }
 
     /**
-     * @expectedException        \LogicException
-     * @expectedExceptionMessage You must start the progress bar
      */
     public function testSetCurrentBeforeStarting()
     {
         $bar = new ProgressBar($this->getOutputStream());
         $bar->setCurrent(15);
+        $this->assertNotNull($bar->getStartTime());
     }
 
     /**
@@ -302,7 +362,7 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
     public function testAddingPlaceholderFormatter()
     {
         ProgressBar::setPlaceholderFormatterDefinition('remaining_steps', function (ProgressBar $bar) {
-            return $bar->getMaxSteps() - $bar->getStep();
+            return $bar->getMaxSteps() - $bar->getCurrent();
         });
         $bar = new ProgressBar($output = $this->getOutputStream(), 3);
         $bar->setFormat(' %remaining_steps% [%bar%]');
@@ -432,9 +492,9 @@ class ProgressBarTest extends \PHPUnit_Framework_TestCase
         );
     }
 
-    protected function getOutputStream($decorated = true)
+    protected function getOutputStream($decorated = true, $verbosity = StreamOutput::VERBOSITY_NORMAL)
     {
-        return new StreamOutput(fopen('php://memory', 'r+', false), StreamOutput::VERBOSITY_NORMAL, $decorated);
+        return new StreamOutput(fopen('php://memory', 'r+', false), $verbosity, $decorated);
     }
 
     protected function generateOutput($expected)