wsd: support experimental features

This adds a new config option to enable/disable
experimental features and behavior. The default
value can be controlled at build time by
--enable-experimental.

Change-Id: Iffcb4c71d9e0933a646251b63033b6dadcd3b809
Signed-off-by: Ashod Nakashian <[email protected]>

common/Common.hpp

@@ -77,8 +77,11 @@ constexpr const char UPLOADING_SUFFIX[] = "ing";
 /// The HTTP response Server. Used only in Responses.
 #define HTTP_SERVER_STRING "COOLWSD HTTP Server " COOLWSD_VERSION
 
-// The client port number, both coolwsd and the kits have this.
+/// The client port number, both coolwsd and the kits have this.
 extern int ClientPortNumber;
 extern std::string MasterLocation;
 
+/// Controls whether experimental features/behavior is enabled or not.
+extern bool EnableExperimental;
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

common/Unit.cpp

@@ -33,6 +33,9 @@ static std::thread TimeoutThread;
 static std::atomic<bool> TimeoutThreadRunning(false);
 std::timed_mutex TimeoutThreadMutex;
 
+/// Controls whether experimental features/behavior is enabled or not.
+bool EnableExperimental = false;
+
 UnitBase *UnitBase::linkAndCreateUnit(UnitType type, const std::string &unitLibPath)
 {
 #if !MOBILEAPP

configure.ac

@@ -352,6 +352,10 @@ AC_ARG_ENABLE([feature-restriction],
               AS_HELP_STRING([--enable-feature-restriction],
                              [Enable control over which uno-commands/feature to disable completely.]))
 
+AC_ARG_ENABLE([experimental],
+              AS_HELP_STRING([--enable-experimental],
+                             [Enable experimental features and behavior]))
+
 
 # Handle options
 AS_IF([test "$enable_debug" = yes -a -n "$with_poco_libs"],
@@ -369,6 +373,8 @@ COOLWSD_ANONYMIZE_USER_DATA=false
 BROWSER_LOGGING="false"
 debug_msg="secure mode: product build"
 anonym_msg=""
+ENABLE_EXPERIMENTAL=false
+experimental_msg="disabled by default"
 bundle_msg="using uglified bundled JS and CSS"
 LOK_LOG_ASSERTIONS=0
 log_asserts_msg="disabled"
@@ -443,6 +449,12 @@ if test -z "$anonym_msg";  then
   anonym_msg="anonymization of user-data is disabled"
 fi
 
+if test "$enable_experimental" = "yes" ; then
+  ENABLE_EXPERIMENTAL=true
+  experimental_msg="enabled by default"
+fi
+AC_SUBST(ENABLE_EXPERIMENTAL)
+
 # macOS: When configuring for building the app itself, on macOS, we need these.
 # But not when just configuring for building the JS on Linux, for copying over
 # to the Mac.
@@ -1531,6 +1543,7 @@ Configuration:
     LO integration tests      ${lo_msg}
     SSL support               $ssl_msg
     Debug & low security      $debug_msg
+    Experimental features     $experimental_msg
     Test assertion logging    $log_asserts_msg
     Uglification and bundling $bundle_msg
     Anonymization             $anonym_msg

coolwsd.xml.in

@@ -16,6 +16,7 @@
     <server_name desc="External hostname:port of the server running coolwsd. If empty, it's derived from the request (please set it if this doesn't work). May be specified when behind a reverse-proxy or when the hostname is not reachable directly." type="string" default=""></server_name>
     <file_server_root_path desc="Path to the directory that should be considered root for the file server. This should be the directory containing cool." type="path" relative="true" default="browser/../"></file_server_root_path>
     <hexify_embedded_urls desc="Enable to protect encoded URLs from getting decoded by intermediate hops. Particularly useful on Azure deployments" type="bool" default="false"></hexify_embedded_urls>
+    <experimental_features desc="Enable/Disable experimental features" type="bool" default="@ENABLE_EXPERIMENTAL@">@ENABLE_EXPERIMENTAL@</experimental_features>
 
     <memproportion desc="The maximum percentage of system memory consumed by all of the @APP_NAME@, after which we start cleaning up idle documents" type="double" default="80.0"></memproportion>
     <num_prespawn_children desc="Number of child processes to keep started in advance and waiting for new clients." type="uint" default="1">1</num_prespawn_children>

kit/ForKit.cpp

@@ -712,6 +712,7 @@ int main(int argc, char** argv)
     // Parse the configuration.
     const auto conf = std::getenv("COOL_CONFIG");
     config::initialize(std::string(conf ? conf : std::string()));
+    EnableExperimental = config::getBool("experimental_features", false);
 #endif
 
     Util::setThreadName("forkit");

wsd/COOLWSD.cpp

@@ -1387,6 +1387,7 @@ void COOLWSD::innerInitialize(Application& self)
         { "child_root_path", "jails" },
         { "file_server_root_path", "browser/.." },
         { "hexify_embedded_urls", "false" },
+        { "experimental_features", "false" },
         { "lo_jail_subpath", "lo" },
         { "logging.protocol", "false" },
         { "logging.anonymize.filenames", "false" }, // Deprecated.
@@ -1544,6 +1545,9 @@ void COOLWSD::innerInitialize(Application& self)
     // Allow UT to manipulate before using configuration values.
     UnitWSD::get().configure(config());
 
+    // Experimental features.
+    EnableExperimental = getConfigValue<bool>(conf, "experimental_features", false);
+
     // Setup user interface mode
     UserInterface = getConfigValue<std::string>(conf, "user_interface.mode", "default");