compute permissions in one place

Author: Arkrissym

Discord.C++/Channel.cpp

@@ -41,21 +41,3 @@ void DiscordCPP::Channel::delete_channel() {
 
     api_call(url, "DELETE");
 }
-
-DiscordCPP::Permissions DiscordCPP::Channel::merge_permission_overwrites(const Permissions& permissions, const std::string& id) {
-    if (permissions.has_permission(Permissions::ADMINISTRATOR)) {
-        return Permissions::All();
-    }
-
-    Permissions result;
-    result.add(permissions);
-
-    for (auto overwrite : permission_overwrites) {
-        if (overwrite.get_id() == id) {
-            result.add(overwrite.get_allowed_permissions());
-            result.remove(overwrite.get_denied_permissions());
-        }
-    }
-
-    return result;
-}

Discord.C++/Channel.h

@@ -52,11 +52,6 @@ class Channel : public DiscordObject {
     /// @return Channelname as std::string
     DLL_EXPORT explicit operator std::string() { return name; };
 
-    /** Merge permission overwrites into given permission set
-        @param permissions permission set
-        @param id member or role id */
-    DLL_EXPORT Permissions merge_permission_overwrites(const Permissions& permissions, const std::string& id);
-
     /// @return the ChannelType of the channel
     DLL_EXPORT Type get_type() { return type; }
     /// @return the sorting position

Discord.C++/ChannelHelper.h

@@ -30,5 +30,9 @@ class ChannelHelper {
     DLL_EXPORT static std::string get_channel_id(const ChannelVariant& channel) {
         return std::visit([](auto& c) { return c.get_id(); }, channel);
     }
+
+    DLL_EXPORT static std::vector<PermissionOverwrites> get_permission_overwrites(const ChannelVariant& channel) {
+        return std::visit([](auto& c) { return c.get_permission_overwrites(); }, channel);
+    }
 };
 }  // namespace DiscordCPP

Discord.C++/Guild.cpp

@@ -200,29 +200,54 @@ void DiscordCPP::Guild::unban(const User& user) {
     api_call(url, "DEL");
 }
 
-DiscordCPP::Permissions DiscordCPP::Guild::get_member_permissions(const Member& member) {
+DiscordCPP::Permissions DiscordCPP::Guild::get_member_permissions(const Member& member, const ChannelVariant& channel) {
     if (owner_id.has_value() && owner_id.value() == member.get_id()) {
         return Permissions::All();
     }
 
+    std::vector<std::string> ids;
+    ids.push_back(this->get_id());  // everyone
+    for (const auto& id : member.get_roles()) {
+        ids.push_back(id);
+    }
+
     std::map<std::string, Permissions> permission_map;
-    for (const Role& role : roles) {
+    for (const auto& role : roles) {
         permission_map.insert({role.get_id(), role.get_permissions()});
     }
 
     Permissions permissions;
-    for (std::string role : member.get_roles()) {
-        if (permission_map.find(role) == permission_map.end()) {
-            throw DiscordException("unknown role " + role + " for member " + member.get_id() + " in guild " + get_id());
+    for (const auto& id : ids) {
+        if (permission_map.find(id) == permission_map.end()) {
+            throw DiscordException("unknown role " + id + " for member " + member.get_id() + " in guild " + get_id());
         }
 
-        if (permission_map.at(role).has_permission(Permissions::ADMINISTRATOR)) {
-            return Permissions::All();
-        }
+        permissions.add(permission_map.at(id));
+    }
+
+    if (permissions.has_permission(Permissions::ADMINISTRATOR)) {
+        return Permissions::All();
+    }
+
+    ids.push_back(member.get_id());
+
+    std::map<std::string, PermissionOverwrites> overwrite_map;
+    for (const auto& overwrite : ChannelHelper::get_permission_overwrites(channel)) {
+        overwrite_map.emplace(overwrite.get_id(), overwrite);
+    }
 
-        permissions.add(permission_map.at(role));
+    Permissions denied;
+    Permissions allowed;
+    for (const auto& id : ids) {
+        if (overwrite_map.find(id) != overwrite_map.end()) {
+            denied.add(overwrite_map.at(id).get_denied_permissions());
+            allowed.add(overwrite_map.at(id).get_allowed_permissions());
+        }
     }
 
+    permissions.remove(denied);
+    permissions.add(allowed);
+
     return permissions;
 }
 

Discord.C++/Guild.h

@@ -151,8 +151,10 @@ class Guild : public DiscordObject {
     DLL_EXPORT void unban(const User& user);
 
     /** @return the members permissions in the guild
+        @param[in]  member  the member whose permissions to check
+        @param[in]  channel the channel to for permission overwrites
         @throws DiscordException if an unknown role is encountered */
-    DLL_EXPORT Permissions get_member_permissions(const Member& member);
+    DLL_EXPORT Permissions get_member_permissions(const Member& member, const ChannelVariant& channel);
 
     /// @return the guild's name
     DLL_EXPORT std::string get_name() { return name; }

test_bot/main.cpp

@@ -471,11 +471,7 @@ class Client : public Discord {
                 Channel channel = interaction.get_channel().value();
                 Guild guild = interaction.get_guild().value();
 
-                Permissions permissions = guild.get_member_permissions(member);
-                permissions = channel.merge_permission_overwrites(permissions, member.get_id());
-                for (auto role : member.get_roles()) {
-                    permissions = channel.merge_permission_overwrites(permissions, role);
-                }
+                Permissions permissions = guild.get_member_permissions(member, channel);
 
                 bool is_admin = permissions.has_permission(DiscordCPP::Permissions::ADMINISTRATOR);
                 bool can_delete_messages = permissions.has_permission(DiscordCPP::Permissions::MANAGE_MESSAGES);