Reporting: Implement garbage collector.

net/reporting/reporting_garbage_collector.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "net/reporting/reporting_garbage_collector.h"
+
+#include <vector>
+
+#include "base/memory/ptr_util.h"
+#include "base/time/tick_clock.h"
+#include "base/time/time.h"
+#include "base/timer/timer.h"
+#include "net/reporting/reporting_cache.h"
+#include "net/reporting/reporting_context.h"
+#include "net/reporting/reporting_observer.h"
+#include "net/reporting/reporting_policy.h"
+#include "net/reporting/reporting_report.h"
+
+namespace net {
+
+namespace {
+
+class ReportingGarbageCollectorImpl : public ReportingGarbageCollector,
+                                      public ReportingObserver {
+ public:
+  ReportingGarbageCollectorImpl(ReportingContext* context)
+      : context_(context), timer_(base::MakeUnique<base::OneShotTimer>()) {
+    context_->AddObserver(this);
+  }
+
+  // ReportingGarbageCollector implementation:
+  //
+  ~ReportingGarbageCollectorImpl() override { context_->RemoveObserver(this); }
+
+  void SetTimerForTesting(std::unique_ptr<base::Timer> timer) override {
+    DCHECK(!timer_->IsRunning());
+    timer_ = std::move(timer);
+  }
+
+  // ReportingObserver implementation:
+  void OnCacheUpdated() override {
+    if (!timer_->IsRunning())
+      StartTimer();
+  }
+
+ private:
+  void StartTimer() {
+    timer_->Start(FROM_HERE, context_->policy().garbage_collection_interval,
+                  base::Bind(&ReportingGarbageCollectorImpl::CollectGarbage,
+                             base::Unretained(this)));
+  }
+
+  void CollectGarbage() {
+    base::TimeTicks now = context_->tick_clock()->NowTicks();
+    const ReportingPolicy& policy = context_->policy();
+
+    std::vector<const ReportingReport*> all_reports;
+    context_->cache()->GetReports(&all_reports);
+
+    std::vector<const ReportingReport*> reports_to_remove;
+    for (const ReportingReport* report : all_reports) {
+      if (now - report->queued >= policy.max_report_age ||
+          report->attempts >= policy.max_report_attempts) {
+        reports_to_remove.push_back(report);
+      }
+    }
+
+    // Don't restart the timer on the garbage collector's own updates.
+    context_->RemoveObserver(this);
+    context_->cache()->RemoveReports(reports_to_remove);
+    context_->AddObserver(this);
+  }
+
+  ReportingContext* context_;
+  std::unique_ptr<base::Timer> timer_;
+};
+
+}  // namespace
+
+// static
+std::unique_ptr<ReportingGarbageCollector> ReportingGarbageCollector::Create(
+    ReportingContext* context) {
+  return base::MakeUnique<ReportingGarbageCollectorImpl>(context);
+}
+
+ReportingGarbageCollector::~ReportingGarbageCollector() {}
+
+}  // namespace net