Improving flat containers interface.

content/browser/devtools/protocol/target_auto_attacher.cc

Index: content/browser/devtools/protocol/target_auto_attacher.cc
diff --git a/content/browser/devtools/protocol/target_auto_attacher.cc b/content/browser/devtools/protocol/target_auto_attacher.cc
index dbccd7b1292946e8f334c65b7d2191ffbe2cf7bb..bc082c5e6e18fe143fc6fb1875d89806b025c8a1 100644
--- a/content/browser/devtools/protocol/target_auto_attacher.cc
+++ b/content/browser/devtools/protocol/target_auto_attacher.cc
@@ -134,7 +134,7 @@ void TargetAutoAttacher::UpdateFrames() {
 }
 
 void TargetAutoAttacher::AgentHostClosed(DevToolsAgentHost* host) {
-  auto_attached_hosts_.erase(host);
+  auto_attached_hosts_.erase(make_scoped_refptr(host));

[danakj, 2017/07/20 15:52:52]

Not for this CL but looks like we should make a comparator for scoped_refptr
keys, and use it for all applicable flat set/maps, so we don't have to do this.

[dyaroshev, 2017/07/20 16:03:18]

I agree. We discussed that earlier in this CL, I even had a general purpose
solution in earlier version of this CL.

 }
 
 void TargetAutoAttacher::ReattachServiceWorkers(bool waiting_for_debugger) {
@@ -165,20 +165,29 @@ void TargetAutoAttacher::ReattachServiceWorkers(bool waiting_for_debugger) {
 void TargetAutoAttacher::ReattachTargetsOfType(const Hosts& new_hosts,
                                                const std::string& type,
                                                bool waiting_for_debugger) {
-  Hosts old_hosts = auto_attached_hosts_;
-  for (auto& it : old_hosts) {
-    DevToolsAgentHost* host = it.get();
-    if (host->GetType() == type && new_hosts.find(host) == new_hosts.end()) {
-      auto_attached_hosts_.erase(host);
-      detach_callback_.Run(host);
-    }
+  // Detach.
+  {
+    Hosts removed_hosts =
+        base::STLSetDifference<Hosts>(new_hosts, auto_attached_hosts_);
+    for (const auto& h : removed_hosts)

[dyaroshev, 2017/07/19 23:38:41]

And I missed GetType check. Ok than, I'll revert this and just fix the
compilation.

[danakj, 2017/07/20 15:52:52]

I'll wait for your update then.

+      detach_callback_.Run(h.get());
   }
-  for (auto& it : new_hosts) {
-    DevToolsAgentHost* host = it.get();
-    if (old_hosts.find(host) == old_hosts.end()) {
-      if (attach_callback_.Run(host, waiting_for_debugger))
-        auto_attached_hosts_.insert(host);
-    }
+
+  // Attach.
+  {
+    Hosts newly_attached_hosts =
+        base::STLSetDifference<Hosts>(auto_attached_hosts_, new_hosts);
+
+    auto_attached_hosts_.clear();
+
+    // Since newly_attached is already a set, inserting in the end is faster
+    // than buffer + sort.
+    std::copy_if(
+        newly_attached_hosts.begin(), newly_attached_hosts.end(),
+        std::inserter(auto_attached_hosts_, auto_attached_hosts_.end()),
+        [&](const scoped_refptr<DevToolsAgentHost>& h) {
+          return attach_callback_.Run(h.get(), waiting_for_debugger);
+        });
   }
 }