Add css coverage example

Author: kklisura

cdt-examples/src/main/java/com/github/kklisura/cdt/examples/CssCoverageExample.java

@@ -0,0 +1,161 @@
+package com.github.kklisura.cdt.examples;
+
+import com.github.kklisura.cdt.launch.ChromeLauncher;
+import com.github.kklisura.cdt.protocol.commands.CSS;
+import com.github.kklisura.cdt.protocol.commands.DOM;
+import com.github.kklisura.cdt.protocol.commands.Page;
+import com.github.kklisura.cdt.protocol.events.page.LoadEventFired;
+import com.github.kklisura.cdt.protocol.support.types.EventHandler;
+import com.github.kklisura.cdt.protocol.support.types.EventListener;
+import com.github.kklisura.cdt.protocol.types.css.CSSStyleSheetHeader;
+import com.github.kklisura.cdt.protocol.types.css.RuleUsage;
+import com.github.kklisura.cdt.services.ChromeDevToolsService;
+import com.github.kklisura.cdt.services.ChromeService;
+import com.github.kklisura.cdt.services.types.ChromeTab;
+import java.util.*;
+import java.util.concurrent.ArrayBlockingQueue;
+import java.util.concurrent.BlockingQueue;
+
+/**
+ * This examples dumps css coverage on github.com
+ *
+ * @author Kenan Klisura
+ */
+public class CssCoverageExample {
+  public static void main(String[] args) throws InterruptedException {
+    // Create chrome launcher.
+    final ChromeLauncher launcher = new ChromeLauncher();
+
+    // Launch chrome either as headless (true) or regular (false).
+    final ChromeService chromeService = launcher.launch(false);
+
+    // Create empty tab ie about:blank.
+    final ChromeTab tab = chromeService.createTab();
+
+    // Get DevTools service to this tab
+    final ChromeDevToolsService devToolsService = chromeService.createDevToolsService(tab);
+
+    final Collection<CoverageData> coverage =
+        new CssCoverage(devToolsService).start("https://github.com");
+
+    System.out.printf(
+        "%92.92s %16.16s %16.16s %16.16s\r\n", "URL", "Total bytes", "Unused bytes", "Coverage");
+
+    for (CoverageData coverageData : coverage) {
+      System.out.printf(
+          "%92.92s %16d %16d %15.2f%%\r\n",
+          coverageData.getUrl(),
+          coverageData.getTotalBytes(),
+          coverageData.getUnusedBytes(),
+          coverageData.getCoverage());
+    }
+
+    devToolsService.close();
+  }
+
+  static class CssCoverage implements EventHandler<LoadEventFired> {
+    private ChromeDevToolsService chromeDevToolsService;
+
+    private EventListener eventListener;
+
+    private BlockingQueue<List<CoverageData>> queue = new ArrayBlockingQueue<>(1);
+    private Map<String, CSSStyleSheetHeader> styleSheets = new HashMap<>();
+
+    CssCoverage(ChromeDevToolsService chromeDevToolsService) {
+      this.chromeDevToolsService = chromeDevToolsService;
+    }
+
+    private void installListenerAndNavigate(String url) {
+      final Page page = chromeDevToolsService.getPage();
+      final CSS css = chromeDevToolsService.getCSS();
+      final DOM dom = chromeDevToolsService.getDOM();
+
+      dom.enable();
+      css.enable();
+
+      css.onStyleSheetAdded(
+          styleSheetAddedEvent -> {
+            final CSSStyleSheetHeader header = styleSheetAddedEvent.getHeader();
+            if (header != null) {
+              styleSheets.put(header.getStyleSheetId(), header);
+            }
+          });
+      css.onStyleSheetRemoved(
+          styleSheetRemovedEvent -> {
+            styleSheets.remove(styleSheetRemovedEvent.getStyleSheetId());
+          });
+
+      this.eventListener = page.onLoadEventFired(this);
+      page.enable();
+      page.navigate(url);
+    }
+
+    @Override
+    public void onEvent(LoadEventFired event) {
+      eventListener.unsubscribe();
+      final CSS css = chromeDevToolsService.getCSS();
+
+      css.startRuleUsageTracking();
+
+      final List<RuleUsage> ruleUsages = css.stopRuleUsageTracking();
+      queue.offer(processCoverageData(ruleUsages));
+    }
+
+    private List<CoverageData> processCoverageData(List<RuleUsage> ruleUsages) {
+      final Map<String, CoverageData> coveragePerSourceURL = new HashMap<>();
+      final Map<String, CoverageData> coverageDataMap = new HashMap<>();
+
+      for (RuleUsage ruleUsage : ruleUsages) {
+        final String styleSheetId = ruleUsage.getStyleSheetId();
+        final CSSStyleSheetHeader cssStyleSheetHeader = styleSheets.get(styleSheetId);
+        final String sourceURL = cssStyleSheetHeader.getSourceURL();
+
+        final CoverageData coverageData =
+            coverageDataMap.computeIfAbsent(
+                styleSheetId,
+                key -> new CoverageData(sourceURL, cssStyleSheetHeader.getLength().longValue()));
+
+        coverageData.unusedBytes -= (ruleUsage.getEndOffset() - ruleUsage.getStartOffset());
+
+        if (sourceURL != null && !sourceURL.isEmpty()) {
+          coveragePerSourceURL.put(sourceURL, coverageData);
+        }
+      }
+
+      return new ArrayList<>(coveragePerSourceURL.values());
+    }
+
+    public List<CoverageData> start(String url) throws InterruptedException {
+      installListenerAndNavigate(url);
+      return queue.take();
+    }
+  }
+
+  static class CoverageData {
+    private final String url;
+    private final long totalBytes;
+    private long unusedBytes;
+
+    public CoverageData(String url, long totalBytes) {
+      this.url = url;
+      this.totalBytes = totalBytes;
+      this.unusedBytes = totalBytes;
+    }
+
+    public String getUrl() {
+      return url;
+    }
+
+    public long getTotalBytes() {
+      return totalBytes;
+    }
+
+    public long getUnusedBytes() {
+      return unusedBytes;
+    }
+
+    public float getCoverage() {
+      return ((float) unusedBytes / totalBytes) * 100;
+    }
+  }
+}