cashew: support additional usage API error result strings

src/service.cc

 // Copyright (c) 2010 The Chromium OS 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 "src/service.h"
 
 #include <glog/logging.h>
 
 #include "src/data_plan_provider.h"
 #include "src/device.h"
@@ skipping 35 matching lines @@
 static const char *kCrosUsageRestrictedProperty = "restricted";
 static const char *kCrosUsagePlansProperty = "plans";
 
 // Chromium OS Usage API version values
 static const int kCrosUsageVersionMinSupported = 1;
 static const int kCrosUsageVersionMaxSupported = 1;
 
 // Chromium OS Usage API status values
 static const char *kCrosUsageStatusOk = "OK";
 static const char *kCrosUsageStatusError = "ERROR";
+static const char *kCrosUsageStatusMalformedRequest = "MALFORMED REQUEST";
+static const char *kCrosUsageStatusInternalError = "INTERNAL ERROR";
+static const char *kCrosUsageStatusServiceUnavailable = "SERVICE UNAVAILABLE";
+static const char *kCrosUsageStatusRequestRefused = "REQUEST REFUSED";
+static const char *kCrosUsageStatusUnknownDevice = "UNKNOWN DEVICE";

[Eric Shienbrood, 2010/10/15 18:43:18]

If you add a new status, you have to modify IsValidCrosUsageStatus() below. It
might be a bit less error prone to define an array of these strings, and have
IsValid search the array for the presence of the supplied string. Something to
keep in mind if you're working in this code in the future.

[Vince Laviano, 2010/10/15 20:25:12]

This is a good point.

Composing a rambling reply to your comment that I've since discarded (the gist
of which was "there would still be some duplication, so we should instead
generate code automatically from a single representation of the status codes")
led me to http://json-schema.org/ (xml-style schema validation for json). 

With a parser that supported this, we could get rid of most of the validation
code in Service::OnRequestComplete and in DataPlan::FromDictionaryValue,
including the code that needs IsValidCrosUsageStatus to exist.

 
 Service::Service(ServiceManager * const parent,
                  DBus::Connection& connection,  // NOLINT
                  const DBus::Path& path)
     : DBus::ObjectProxy(connection, path, kFlimflamServiceName),
       parent_(CHECK_NOTNULL(parent)), connection_(connection), path_(path),
       state_(kStateUnknown), type_(kTypeUnknown), device_(NULL),
       provider_(NULL), request_in_progress_(false),
       update_timeout_source_(NULL), policy_(NULL) {
   // init our state with a GetProperties() call to our Flimflam service path
@@ skipping 144 matching lines @@
         << ", " << kCrosUsageVersionMaxSupported << "]";
     return;
   }
 
   std::string status;
   if (!root->GetString(kCrosUsageStatusProperty, &status)) {
     LOG(WARNING) << path_ << ": OnRequestComplete: no status property";
     return;
   }
   DLOG(INFO) << path_ << ": OnRequestComplete: status = " << status;
-  if (status != kCrosUsageStatusOk && status != kCrosUsageStatusError) {
+  if (!IsValidCrosUsageStatus(status)) {
     LOG(WARNING) << path_ << ": OnRequestComplete: invalid status: " << status;
     return;
   }
-  if (status == kCrosUsageStatusError) {
+  if (status != kCrosUsageStatusOk) {
     LOG(WARNING) << path_ << ": OnRequestComplete: status: " << status;
+    OnCrosUsageErrorResult(status);
     return;
   }
 
   bool restricted = false;
   if (root->GetBoolean(kCrosUsageRestrictedProperty, &restricted)) {
     DLOG(INFO) << path_ << ": OnRequestComplete: restricted = " << restricted;
   } else {
     DLOG(INFO) << path_ << ": OnRequestComplete: no restricted property";
     // restricted property is optional
   }
@@ skipping 326 matching lines @@
   }
   DestroyUpdateTimer();
   CancelPendingRequests();
   if (provider_ != NULL) {
     DLOG(INFO) << path_ << ": DeleteCarrierState: deleting data plan provider";
     delete provider_;
     provider_ = NULL;
   }
 }
 
+bool Service::IsValidCrosUsageStatus(const std::string& status) const {
+  if (status == kCrosUsageStatusOk ||
+      status == kCrosUsageStatusError ||
+      status == kCrosUsageStatusMalformedRequest ||
+      status == kCrosUsageStatusInternalError ||
+      status == kCrosUsageStatusServiceUnavailable ||
+      status == kCrosUsageStatusRequestRefused ||
+      status == kCrosUsageStatusUnknownDevice) {
+    return true;
+  }
+  return false;
+}
+
+void Service::OnCrosUsageErrorResult(const std::string& status) {
+  DLOG(WARNING) << path_ << ": OnCrosUsageErrorResult: " << status;
+  // TODO(vlaviano): take action based on which specific error status string
+  // we've received (e.g., we could adjust the update timer interval, or
+  // disable the timer entirely).
+}
+
 }  // namespace cashew