Remove sleeps from curl handling, select it is responsible for waiting

The current sleeps mean that large files download slowly as select would
return quickly when data has arrived and needs to be processed, but the
sleep waits while the buffers are full.

On the flipside we need to ensure that some code that would keep the CPU
busy if run too often does not get run every time select returns.

src/Composer/Util/Http/CurlDownloader.php

@@ -49,6 +49,7 @@ class CurlDownloader
         CURLM_OUT_OF_MEMORY => array('CURLM_OUT_OF_MEMORY', 'You are doomed.'),
         CURLM_INTERNAL_ERROR => array('CURLM_INTERNAL_ERROR', 'This can only be returned if libcurl bugs. Please report it to us!'),
     );
+    private $lastInfoUpdate = 0;
 
     private static $options = array(
         'http' => array(
@@ -240,6 +241,7 @@ class CurlDownloader
         }
 
         $this->checkCurlResult(curl_multi_add_handle($this->multiHandle, $curlHandle));
+        $this->lastInfoUpdate = 0;
         // TODO progress
 
         return (int) $curlHandle;
@@ -390,30 +392,35 @@ class CurlDownloader
             }
         }
 
-        foreach ($this->jobs as $i => $curlHandle) {
-            if (!isset($this->jobs[$i])) {
-                continue;
-            }
-            $curlHandle = $this->jobs[$i]['curlHandle'];
-            $progress = array_diff_key(curl_getinfo($curlHandle), self::$timeInfo);
+        if (microtime(true) - $this->lastInfoUpdate > 0.1) {
+            $this->lastInfoUpdate = microtime(true);
 
-            if ($this->jobs[$i]['progress'] !== $progress) {
-                $this->jobs[$i]['progress'] = $progress;
-
-                if (isset($this->jobs[$i]['options']['max_file_size'])) {
-                    // Compare max_file_size with the content-length header this value will be -1 until the header is parsed
-                    if ($this->jobs[$i]['options']['max_file_size'] < $progress['download_content_length']) {
-                        throw new MaxFileSizeExceededException('Maximum allowed download size reached. Content-length header indicates ' . $progress['download_content_length'] . ' bytes. Allowed ' .  $this->jobs[$i]['options']['max_file_size'] . ' bytes');
+            foreach ($this->jobs as $i => $curlHandle) {
+                if (!isset($this->jobs[$i])) {
+                    continue;
+                }
+                $curlHandle = $this->jobs[$i]['curlHandle'];
+                $progress = array_diff_key(curl_getinfo($curlHandle), self::$timeInfo);
+
+                if ($this->jobs[$i]['progress'] !== $progress) {
+                    $this->jobs[$i]['progress'] = $progress;
+
+                    if (isset($this->jobs[$i]['options']['max_file_size'])) {
+                        // Compare max_file_size with the content-length header this value will be -1 until the header is parsed
+                        if ($this->jobs[$i]['options']['max_file_size'] < $progress['download_content_length']) {
+                            throw new MaxFileSizeExceededException('Maximum allowed download size reached. Content-length header indicates ' . $progress['download_content_length'] . ' bytes. Allowed ' .  $this->jobs[$i]['options']['max_file_size'] . ' bytes');
+                        }
+
+                        // Compare max_file_size with the download size in bytes
+                        if ($this->jobs[$i]['options']['max_file_size'] < $progress['size_download']) {
+                            throw new MaxFileSizeExceededException('Maximum allowed download size reached. Downloaded ' . $progress['size_download'] . ' of allowed ' .  $this->jobs[$i]['options']['max_file_size'] . ' bytes');
+                        }
                     }
 
-                    // Compare max_file_size with the download size in bytes
-                    if ($this->jobs[$i]['options']['max_file_size'] < $progress['size_download']) {
-                        throw new MaxFileSizeExceededException('Maximum allowed download size reached. Downloaded ' . $progress['size_download'] . ' of allowed ' .  $this->jobs[$i]['options']['max_file_size'] . ' bytes');
-                    }
+                    // TODO progress
                 }
-
-                // TODO progress
             }
+
         }
     }
 

src/Composer/Util/HttpDownloader.php

@@ -340,8 +340,6 @@ class HttpDownloader
             if (!$this->countActiveJobs($index)) {
                 return;
             }
-
-            usleep(1000);
         }
     }
 

src/Composer/Util/Loop.php

@@ -85,6 +85,7 @@ class Loop
             $progress->start($totalJobs);
         }
 
+        $lastUpdate = 0;
         while (true) {
             $activeJobs = 0;
 
@@ -95,15 +96,20 @@ class Loop
                 $activeJobs += $this->processExecutor->countActiveJobs();
             }
 
-            if ($progress) {
+            if ($progress && microtime(true) - $lastUpdate > 0.1) {
+                $lastUpdate = microtime(true);
+                echo "setting progress\n";
                 $progress->setProgress($progress->getMaxSteps() - $activeJobs);
             }
 
             if (!$activeJobs) {
                 break;
             }
+        }
 
-            usleep(5000);
+        // as we skip progress updates if they are too quick, make sure we do one last one here at 100%
+        if ($progress) {
+            $progress->setProgress($progress->getMaxSteps());
         }
 
         unset($this->currentPromises[$waitIndex]);