[object-stats] Unpack gzipped trace files on the fly

No-try: true
Bug: v8:7266
Change-Id: I9ca2036a54c55c754cc2bb69dcca6157f88ea0fa
Reviewed-on: https://chromium-review.googlesource.com/880960Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50807}

tools/heap-stats/README.md

@@ -6,8 +6,9 @@ maintaining internal state versus actually allocated by the user.
 
 The tool consumes log files produced by d8 (or Chromium) by passing
 `--trace-gc-object-stats` or a trace captured using Chrome's tracing
-infrastructure. Chrome trace files need to be unpacked before they can
-be used though.
+infrastructure. Chrome trace files can either be processed as gzip or raw text
+files.
+
 
 Hosting requires a web server, e.g.:
 

tools/heap-stats/index.html

@@ -9,7 +9,12 @@ found in the LICENSE file. -->
   <meta charset="UTF-8">
   <title>V8 Heap Statistics</title>
   <link href='https://fonts.googleapis.com/css?family=Roboto' rel='stylesheet' type='text/css'>
-  <script type="text/javascript" src="https://www.gstatic.com/charts/loader.js"></script>
+  <script type="text/javascript"
+          src="https://www.gstatic.com/charts/loader.js"></script>
+  <script type="text/javascript"
+          src="https://cdnjs.cloudflare.com/ajax/libs/pako/1.0.6/pako_inflate.min.js"
+          integrity="sha256-N1z6ddQzX83fjw8v7uSNe7/MgOmMKdwFUv1+AJMDqNM="
+          crossorigin="anonymous"></script>
 
   <link rel="import" href="details-selection.html">
   <link rel="import" href="global-timeline.html">
@@ -73,8 +78,7 @@ function globalSelectionChangedA(e) {
       <a
         href="https://www.chromium.org/developers/how-tos/trace-event-profiling-tool">Chrome's
         tracing infrastructure</a> collecting data for the category
-      <code>v8.gc_stats</code>. The trace file needs to be unpacked (e.g. using
-      <code>gunzip</code>).
+      <code>v8.gc_stats</code>.
     </li>
   </ul>
   <p>

tools/heap-stats/trace-file-reader.js

@@ -50,17 +50,32 @@ class TraceFileReader extends HTMLElement {
       return;
     }
 
-    const result = new FileReader();
-    result.onload = (e) => {
-      let contents = e.target.result.split('\n');
-      const return_data = (e.target.result.includes('V8.GC_Objects_Stats')) ?
-          this.createModelFromChromeTraceFile(contents) :
-          this.createModelFromV8TraceFile(contents);
-      this.updateLabel('Finished loading \'' + file.name + '\'.');
-      this.dispatchEvent(new CustomEvent(
-          'change', {bubbles: true, composed: true, detail: return_data}));
-    };
-    result.readAsText(file);
+    const reader = new FileReader();
+
+    if (file.type === 'application/gzip') {
+      reader.onload = (e) => {
+        try {
+          const textResult = pako.inflate(e.target.result, {to: 'string'});
+          this.processRawText(file, textResult);
+        } catch (err) {
+          console.error(err);
+        }
+      };
+      reader.readAsArrayBuffer(file);
+    } else {
+      reader.onload = (e) => this.processRawText(file, e.target.result);
+      reader.readAsText(file);
+    }
+  }
+
+  processRawText(file, result) {
+    let contents = result.split('\n');
+    const return_data = (result.includes('V8.GC_Objects_Stats')) ?
+        this.createModelFromChromeTraceFile(contents) :
+        this.createModelFromV8TraceFile(contents);
+    this.updateLabel('Finished loading \'' + file.name + '\'.');
+    this.dispatchEvent(new CustomEvent(
+        'change', {bubbles: true, composed: true, detail: return_data}));
   }
 
   createOrUpdateEntryIfNeeded(data, keys, entry) {
@@ -193,7 +208,7 @@ class TraceFileReader extends HTMLElement {
         });
       });
     } catch (e) {
-      console.log('Unable to parse chrome trace file.', e);
+      console.error('Unable to parse chrome trace file.', e);
     }
     this.extendAndSanitizeModel(data, keys);
     return data;