Add the Copresence API.

chrome/browser/extensions/api/copresence/copresence_translations.cc

+// Copyright 2014 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 "chrome/browser/extensions/api/copresence/copresence_translations.h"
+
+#include "chrome/common/extensions/api/copresence.h"
+#include "components/copresence/proto/data.pb.h"
+#include "components/copresence/proto/enums.pb.h"
+#include "components/copresence/proto/rpcs.pb.h"
+
+namespace {
+
+const int kDefaultTimeToLiveMs = 5 * 60 * 1000;    // 5 minutes.
+const int kMaxTimeToLiveMs = 24 * 60 * 60 * 1000;  // 24 hours.
+
+// Checks and returns the ttl provided by the user. If invalid, returns -1.
+int SanitizeTtl(int* user_ttl) {
+  return !user_ttl
+             ? kDefaultTimeToLiveMs
+             : *user_ttl <= 0 || *user_ttl > kMaxTimeToLiveMs ? -1 : *user_ttl;

[Daniel Erat, 2014/08/06 22:59:37]

use parentheses for nested ternary operators

[rkc, 2014/08/07 02:18:33]

Done.

+}
+
+copresence::BroadcastScanConfiguration TranslateStrategy(
+    extensions::api::copresence::Strategy* strategy) {

[Daniel Erat, 2014/08/06 22:59:37]

const reference?

[rkc, 2014/08/07 02:18:33]

copresence::BroadcastScanConfiguration is an enum, so const ref doesn't do much
for us.

[rkc, 2014/08/07 02:42:36]

Oh, for some weird reason I thought you were saying this should 'return' a const
reference.
Fixed the parameter to be const ref.
Done.

+  bool only_broadcast = false;
+  bool only_scan = false;

[Daniel Erat, 2014/08/06 22:59:37]

this isn't limited to this change, but the word "only" doesn't make sense if
both of these can be set. should it be something like "should_broadcast" and
"should_scan" instead?

and how does this relate to the comments in the idl?

+  dictionary Strategy {
+    // Attempt to use low power mode. Defaults to false.
+    boolean? lowPower;
+    // Attempt to only broadcast. Using this with onlyScan can result in both
+    // being ignored. Defaults to false.
+    boolean? onlyBroadcast;
+    // Attempt to only scan. Using this with onlyBroadcast can result in both
+    // being ignored. Defaults to false.
+    boolean? onlyScan;
+    // Attempt to use audible audio. Defaults to false.
+    boolean? audible;
+  };

and if you really want only one mode to be set, why not use an enum?

[rkc, 2014/08/07 02:18:33]

There is no good way to restrict an app to setting only one of the two
(onlyScan/onlyBroadcast) strategies. If this was an enum, the app could simply
pass in two strategy objects, one setting onlyScan and one setting
onlyBroadcast. Furthermore, if one app sets onlyScan, and another sets
onlyBroadcast, we'll end up doing both anyway since the server will give us a
broadcast directive for one app, and a scan directive for the other.

So with these restrictions, it made sense to optimize for the simplicity of the
strategy object. This used to be just a list of enums. The app would pass us an
array of all the enums it wanted to use (that also had the same problem though,
an app could pass in an onlyScan and onlyBroadcast enum). We changed this to be
an object so we can later add maybe more complex strategies which would be hard
to express as an enum.

In scenarios that we don't have conflicting strategies, "only" does truly mean
"only", hence the naming. We do make it clear in documentation that these are
just suggestions and that in various situations (this is one case, more might
show up later), we may or may not respect the suggestion given to us.

+
+  if (strategy->only_broadcast && *strategy->only_broadcast)

[Daniel Erat, 2014/08/06 22:59:37]

how about just combining these with the earlier statements?

  bool broadcast = strategy.broadcast && *strategy.broadcast;

[rkc, 2014/08/07 02:18:33]

Done.

+    only_broadcast = true;
+  if (strategy->only_scan && *strategy->only_scan)
+    only_scan = true;
+
+  if (only_broadcast && only_scan)
+    return copresence::BROADCAST_AND_SCAN;
+  if (only_broadcast)
+    return copresence::BROADCAST_ONLY;
+  if (only_scan)
+    return copresence::SCAN_ONLY;
+
+  return copresence::BROADCAST_SCAN_CONFIGURATION_UNKNOWN;
+}
+
+}  // namespace
+
+namespace extensions {
+
+bool AddPublishToRequest(const std::string& app_id,
+                         const api::copresence::PublishOperation& publish,
+                         copresence::ReportRequest* request) {
+  copresence::PublishedMessage* publish_proto =
+      request->mutable_manage_messages_request()->add_message_to_publish();
+  publish_proto->mutable_access_policy()->mutable_acl()->set_acl_type(
+      copresence::NO_ACL_CHECK);
+  publish_proto->set_id(publish.id);
+  publish_proto->mutable_message()->mutable_type()->set_type(
+      publish.message.type);
+  publish_proto->mutable_message()->set_payload(publish.message.payload);
+
+  int ttl = SanitizeTtl(publish.time_to_live_millis.get());
+  if (ttl < 0)

[Daniel Erat, 2014/08/06 22:59:37]

is there any way to report what the problem is to the caller?

[rkc, 2014/08/07 02:18:33]

Yes, we have a bug open tracking better error reporting to the caller
(crbug.com/390389). We'll be doing another parse through all of this code to add
in better error reporting when we work on that issue.

+    return false;
+  publish_proto->mutable_access_policy()->set_ttl_millis(ttl);
+
+  // TODO(rkc): This is a temporary hack; eventually namespaces will be
+  // completely gone. When that happens, remove this.
+  publish_proto->mutable_message()->mutable_type()->set_namespace_deprecated(
+      app_id);
+  publish_proto->set_strategy(copresence::AGGRESSIVE);
+
+  if (publish.strategies.get()) {
+    copresence::BroadcastScanConfiguration config =
+        TranslateStrategy(publish.strategies.get());
+    if (config != copresence::BROADCAST_SCAN_CONFIGURATION_UNKNOWN) {
+      copresence::TokenExchangeStrategy* strategy_proto =
+          publish_proto->mutable_token_exchange_strategy();
+      strategy_proto->set_broadcast_scan_configuration(config);
+    }
+  }
+
+  DVLOG(2) << "Publishing message of type " << publish.message.type << ":\n"
+           << publish.message.payload;
+  // TODO(ckehoe): Validate that required fields are non-empty, etc.
+  return true;
+}
+
+bool AddUnpublishToRequest(const std::string& publish_id,
+                           copresence::ReportRequest* request) {
+  if (publish_id.empty())
+    return false;
+
+  request->mutable_manage_messages_request()->add_id_to_unpublish(publish_id);
+  DVLOG(2) << "Unpublishing message \"" << publish_id << "\"";
+  return true;
+}
+
+bool AddSubscribeToRequest(
+    const std::string& app_id,
+    const api::copresence::SubscribeOperation& subscription,
+    SubscriptionToAppMap* apps_by_subscription_id,
+    copresence::ReportRequest* request) {
+  // Associate the subscription id with the app id.
+  SubscriptionToAppMap::iterator previous_subscription =
+      apps_by_subscription_id->find(subscription.id);
+  if (previous_subscription == apps_by_subscription_id->end()) {
+    (*apps_by_subscription_id)[subscription.id] = app_id;
+  } else if (previous_subscription->second == app_id) {
+    VLOG(2) << "Overwriting subscription id \"" << subscription.id
+            << "\" for app \"" << app_id << "\"";
+  } else {
+    // A conflicting association exists already.
+    VLOG(1) << "Subscription id \"" << subscription.id
+            << "\" used by two apps: \"" << previous_subscription->second
+            << "\" and \"" << app_id << "\"";
+    return false;
+  }
+
+  // Convert from client to server subscription format.
+  copresence::Subscription* subscription_proto =
+      request->mutable_manage_subscriptions_request()->add_subscription();
+  subscription_proto->set_id(subscription.id);
+  int ttl = SanitizeTtl(subscription.time_to_live_millis.get());
+  if (ttl < 0)
+    return false;
+  subscription_proto->set_ttl_millis(ttl);
+
+  // TODO(rkc): This is a temporary hack; eventually namespaces will be
+  // completely gone. When that happens, remove this.
+  subscription_proto->mutable_message_type()->set_namespace_deprecated(app_id);
+  subscription_proto->set_strategy(copresence::AGGRESSIVE);
+
+  subscription_proto->mutable_message_type()->set_type(
+      subscription.filter.type);
+
+  if (subscription.strategies.get()) {
+    copresence::BroadcastScanConfiguration config =
+        TranslateStrategy(subscription.strategies.get());
+    if (config != copresence::BROADCAST_SCAN_CONFIGURATION_UNKNOWN) {
+      copresence::TokenExchangeStrategy* strategy_proto =
+          subscription_proto->mutable_token_exchange_strategy();
+      strategy_proto->set_broadcast_scan_configuration(config);
+    }
+  }
+
+  DVLOG(2) << "Subscribing for messages of type " << subscription.filter.type;
+  // TODO(ckehoe): Validate that required fields are non-empty, etc.
+  return true;
+}
+
+bool AddUnsubscribeToRequest(const std::string& app_id,
+                             const std::string& subscription_id,
+                             SubscriptionToAppMap* apps_by_subscription_id,
+                             copresence::ReportRequest* request) {
+  if (subscription_id.empty())
+    return false;
+
+  // Check that this subscription id belongs to this app.
+  SubscriptionToAppMap::iterator subscription =
+      apps_by_subscription_id->find(subscription_id);
+  if (subscription == apps_by_subscription_id->end()) {
+    LOG(ERROR) << "No such subscription \"" << subscription_id
+               << "\". Cannot unsubscribe.";
+    return false;
+  } else if (subscription->second != app_id) {
+    LOG(ERROR) << "Subscription \"" << subscription_id
+               << "\" does not belong to app \"" << app_id
+               << "\". Cannot unsubscribe.";
+    return false;
+  } else {
+    apps_by_subscription_id->erase(subscription);
+  }
+
+  request->mutable_manage_subscriptions_request()->add_id_to_unsubscribe(
+      subscription_id);
+  DVLOG(2) << "Cancelling subscription \"" << subscription_id << "\" for app \""
+           << app_id << "\"";
+  return true;
+}
+
+bool PrepareReportRequestProto(
+    const std::vector<linked_ptr<api::copresence::Operation> >& operations,
+    const std::string& app_id,
+    SubscriptionToAppMap* apps_by_subscription_id,
+    copresence::ReportRequest* request) {
+  for (size_t i = 0; i < operations.size(); ++i) {
+    linked_ptr<api::copresence::Operation> op = operations[i];
+    DCHECK(op.get());
+
+    // Verify our object has exactly one operation.
+    if (static_cast<int>(op->publish != NULL) +
+        static_cast<int>(op->subscribe != NULL) +
+        static_cast<int>(op->unpublish != NULL) +
+        static_cast<int>(op->unsubscribe != NULL) != 1) {
+      return false;
+    }
+
+    if (op->publish) {
+      if (!AddPublishToRequest(app_id, *(op->publish), request))
+        return false;
+    }

[Daniel Erat, 2014/08/06 22:59:37]

nit: since you're already checking earlier that only one is set, you could
condense this a bit by using if-else

[rkc, 2014/08/07 02:18:33]

Done.

+
+    if (op->subscribe) {
+      if (!AddSubscribeToRequest(
+              app_id, *(op->subscribe), apps_by_subscription_id, request))
+        return false;
+    }
+
+    if (op->unpublish) {
+      if (!AddUnpublishToRequest(op->unpublish->unpublish_id, request))
+        return false;
+    }
+
+    if (op->unsubscribe) {
+      if (!AddUnsubscribeToRequest(app_id,
+                                   op->unsubscribe->unsubscribe_id,
+                                   apps_by_subscription_id,
+                                   request))
+        return false;
+    }
+  }
+
+  return true;
+}
+
+}  // namespace extensions