Issue 4127 - [emscripten] Convert subscription classes to C++ - Part 1

compiled/subscription/Subscription.cpp

+#include <cstdio>
+#include <cstdlib>
+
+#include "Subscription.h"
+#include "DownloadableSubscription.h"
+#include "UserDefinedSubscription.h"
+#include "../StringMap.h"
+
+namespace
+{
+  StringMap<Subscription*> knownSubscriptions(16);
+}
+
+Subscription::Subscription(Type type, const String& id)
+    : mType(type), mID(id), mDisabled(false)
+{
+  annotate_address(this, "Subscription");
+}
+
+Subscription::~Subscription()
+{
+  knownSubscriptions.erase(mID);
+}
+
+OwnedString Subscription::Serialize() const
+{
+  OwnedString result(u"[Subscription]\nurl="_str);
+  result.append(mID);
+  result.append(u'\n');
+  if (!mTitle.empty())
+  {
+    result.append(u"title="_str);
+    result.append(mTitle);
+    result.append(u'\n');
+  }
+  if (mDisabled)
+    result.append(u"disabled=true\n"_str);
+
+  return result;
+}
+
+OwnedString Subscription::SerializeFilters() const
+{
+  // TODO
+  return OwnedString();
+}
+
+Subscription* Subscription::FromID(const String& id)
+{
+  if (id.empty())
+  {
+    // Generate a new random ID
+    unsigned seed = knownSubscriptions.size();
+    OwnedString randomID(u"~user~000000"_str);
+    do
+    {
+      int number = rand_r(&seed);
+      for (int i = randomID.length() - 6; i < randomID.length(); i++)
+      {
+        randomID[i] = '0' + (number % 10);
+        number /= 10;
+      }
+    } while (knownSubscriptions.find(randomID));
+    return FromID(randomID);
+  }
+
+  auto knownSubscription = knownSubscriptions.find(id);
+  if (knownSubscription)
+  {
+    knownSubscription->second->AddRef();
+    return knownSubscription->second;
+  }
+
+  SubscriptionPtr subscription;
+  if (!id.empty() && id[0] == '~')
+    subscription = new UserDefinedSubscription(id);
+  else
+    subscription = new DownloadableSubscription(id);
+
+  // This is a hack: we looked up the entry using id but create it using
+  // subscription->mID. This works because both are equal at this point.
+  // However, id refers to a temporary buffer which will go away.
+  enter_context("Adding to known subscriptions");
+  knownSubscription.assign(subscription->mID, subscription.get());
+  exit_context();
+
+  return subscription.release();
+}