1 files changed, 71 insertions, 15 deletions

diff --git a/Userland/Services/ConfigServer/ClientConnection.cpp b/Userland/Services/ConfigServer/ClientConnection.cpp
index 3551a1af5b..246a95e10f 100644
--- a/Userland/Services/ConfigServer/ClientConnection.cpp
+++ b/Userland/Services/ConfigServer/ClientConnection.cpp
@@ -12,6 +12,25 @@ namespace ConfigServer {
 
 static HashMap<int, RefPtr<ClientConnection>> s_connections;
 
+struct CachedDomain {
+    String domain;
+    NonnullRefPtr<Core::ConfigFile> config;
+};
+
+static HashMap<String, NonnullOwnPtr<CachedDomain>> s_cache;
+
+static Core::ConfigFile& ensure_domain_config(String const& domain)
+{
+    auto it = s_cache.find(domain);
+    if (it != s_cache.end())
+        return *it->value->config;
+
+    auto config = Core::ConfigFile::open_for_app(domain, Core::ConfigFile::AllowWriting::Yes);
+    auto cache_entry = make<CachedDomain>(domain, config);
+    s_cache.set(domain, move(cache_entry));
+    return *config;
+}
+
 ClientConnection::ClientConnection(NonnullRefPtr<Core::LocalSocket> client_socket, int client_id)
     : IPC::ClientConnection<ConfigClientEndpoint, ConfigServerEndpoint>(*this, move(client_socket), client_id)
 {
@@ -38,6 +57,16 @@ void ClientConnection::pledge_domains(Vector<String> const& domains)
         m_pledged_domains.set(domain);
 }
 
+void ClientConnection::monitor_domain(String const& domain)
+{
+    if (m_has_pledged && !m_pledged_domains.contains(domain)) {
+        did_misbehave("Attempt to monitor non-pledged domain");
+        return;
+    }
+
+    m_monitored_domains.set(domain);
+}
+
 bool ClientConnection::validate_access(String const& domain, String const& group, String const& key)
 {
     if (!m_has_pledged)
@@ -53,10 +82,10 @@ Messages::ConfigServer::ReadStringValueResponse ClientConnection::read_string_va
     if (!validate_access(domain, group, key))
         return nullptr;
 
-    auto config = Core::ConfigFile::open_for_app(domain);
-    if (!config->has_key(group, key))
+    auto& config = ensure_domain_config(domain);
+    if (!config.has_key(group, key))
         return Optional<String> {};
-    return Optional<String> { config->read_entry(group, key) };
+    return Optional<String> { config.read_entry(group, key) };
 }
 
 Messages::ConfigServer::ReadI32ValueResponse ClientConnection::read_i32_value(String const& domain, String const& group, String const& key)
@@ -64,10 +93,10 @@ Messages::ConfigServer::ReadI32ValueResponse ClientConnection::read_i32_value(St
     if (!validate_access(domain, group, key))
         return nullptr;
 
-    auto config = Core::ConfigFile::open_for_app(domain);
-    if (!config->has_key(group, key))
+    auto& config = ensure_domain_config(domain);
+    if (!config.has_key(group, key))
         return Optional<i32> {};
-    return Optional<i32> { config->read_num_entry(group, key) };
+    return Optional<i32> { config.read_num_entry(group, key) };
 }
 
 Messages::ConfigServer::ReadBoolValueResponse ClientConnection::read_bool_value(String const& domain, String const& group, String const& key)
@@ -75,10 +104,10 @@ Messages::ConfigServer::ReadBoolValueResponse ClientConnection::read_bool_value(
     if (!validate_access(domain, group, key))
         return nullptr;
 
-    auto config = Core::ConfigFile::open_for_app(domain);
-    if (!config->has_key(group, key))
+    auto& config = ensure_domain_config(domain);
+    if (!config.has_key(group, key))
         return Optional<bool> {};
-    return Optional<bool> { config->read_bool_entry(group, key) };
+    return Optional<bool> { config.read_bool_entry(group, key) };
 }
 
 void ClientConnection::write_string_value(String const& domain, String const& group, String const& key, String const& value)
@@ -86,8 +115,17 @@ void ClientConnection::write_string_value(String const& domain, String const& gr
     if (!validate_access(domain, group, key))
         return;
 
-    auto config = Core::ConfigFile::open_for_app(domain, Core::ConfigFile::AllowWriting::Yes);
-    config->write_entry(group, key, value);
+    auto& config = ensure_domain_config(domain);
+
+    if (config.has_key(group, key) && config.read_entry(group, key) == value)
+        return;
+
+    config.write_entry(group, key, value);
+
+    for (auto& it : s_connections) {
+        if (it.value != this && it.value->m_monitored_domains.contains(domain))
+            it.value->async_notify_changed_string_value(domain, group, key, value);
+    }
 }
 
 void ClientConnection::write_i32_value(String const& domain, String const& group, String const& key, i32 value)
@@ -95,8 +133,17 @@ void ClientConnection::write_i32_value(String const& domain, String const& group
     if (!validate_access(domain, group, key))
         return;
 
-    auto config = Core::ConfigFile::open_for_app(domain, Core::ConfigFile::AllowWriting::Yes);
-    config->write_num_entry(group, key, value);
+    auto& config = ensure_domain_config(domain);
+
+    if (config.has_key(group, key) && config.read_num_entry(group, key) == value)
+        return;
+
+    config.write_num_entry(group, key, value);
+
+    for (auto& it : s_connections) {
+        if (it.value != this && it.value->m_monitored_domains.contains(domain))
+            it.value->async_notify_changed_i32_value(domain, group, key, value);
+    }
 }
 
 void ClientConnection::write_bool_value(String const& domain, String const& group, String const& key, bool value)
@@ -104,8 +151,17 @@ void ClientConnection::write_bool_value(String const& domain, String const& grou
     if (!validate_access(domain, group, key))
         return;
 
-    auto config = Core::ConfigFile::open_for_app(domain, Core::ConfigFile::AllowWriting::Yes);
-    config->write_bool_entry(group, key, value);
+    auto& config = ensure_domain_config(domain);
+
+    if (config.has_key(group, key) && config.read_bool_entry(group, key) == value)
+        return;
+
+    config.write_bool_entry(group, key, value);
+
+    for (auto& it : s_connections) {
+        if (it.value != this && it.value->m_monitored_domains.contains(domain))
+            it.value->async_notify_changed_bool_value(domain, group, key, value);
+    }
 }
 
 }