Configuration: Split options into global and per-module configuration.

This lets each module define its own options, without needing the option names
to be unique across all modules.

Also organises the module-specific options into their own sections at the end
of the help text.

include/platform/mir/options/configuration.h

@@ -23,6 +23,8 @@
 
 namespace mir
 {
+class SharedLibrary;
+
 namespace options
 {
 extern char const* const arw_server_socket_opt;
@@ -66,17 +68,24 @@ extern char const* const auto_console;
 
 extern char const* const vt_option_name;
 
-class Configuration
+class OptionsProvider
 {
 public:
-    virtual std::shared_ptr<options::Option> the_options() const = 0;
+    /**
+     * The options not associated with a specific loaded module
+     */
+    virtual std::shared_ptr<options::Option> global_options() const = 0;
+    /**
+     * All options, including those added by the specified module
+     */
+    virtual auto the_options_for(SharedLibrary const& module) const -> std::shared_ptr<options::Option> = 0;
 
 protected:
+    OptionsProvider() = default;
+    virtual ~OptionsProvider() = default;
 
-    Configuration() = default;
-    virtual ~Configuration() = default;
-    Configuration(Configuration const&) = delete;
-    Configuration& operator=(Configuration const&) = delete;
+    OptionsProvider(OptionsProvider const&) = delete;
+    OptionsProvider& operator=(OptionsProvider const&) = delete;
 };
 }
 }

include/platform/mir/options/default_configuration.h

@@ -19,15 +19,15 @@
 
 #include "mir/options/configuration.h"
 #include "mir/options/program_option.h"
+#include "mir/shared_library.h"
 #include <boost/program_options/options_description.hpp>
 #include <vector>
 
 namespace mir
 {
-class SharedLibrary;
 namespace options
 {
-class DefaultConfiguration : public Configuration
+class DefaultConfiguration : public OptionsProvider
 {
 public:
     DefaultConfiguration(int argc, char const* argv[]);
@@ -54,7 +54,8 @@ class DefaultConfiguration : public Configuration
 
     void add_platform_options();
     // accessed via the base interface, when access to add_options() has been "lost"
-    std::shared_ptr<options::Option> the_options() const override;
+    std::shared_ptr<options::Option> global_options() const override;
+    auto the_options_for(SharedLibrary const& module) const -> std::shared_ptr<Option> override;
 
     virtual void parse_arguments(
         boost::program_options::options_description desc,
@@ -74,6 +75,47 @@ class DefaultConfiguration : public Configuration
     char const** const argv;
     std::function<void(int argc, char const* const* argv)> const unparsed_arguments_handler;
     std::shared_ptr<boost::program_options::options_description> const program_options;
+
+    template<typename Value>
+    class LibraryMap
+    {
+    private:
+        std::vector<std::pair<mir::SharedLibrary::Handle, Value>> values;
+
+        auto find(SharedLibrary const&) -> decltype(values)::iterator;
+        auto find(SharedLibrary const&) const -> decltype(values)::const_iterator;
+    public:
+        LibraryMap() = default;
+        ~LibraryMap() = default;
+
+        auto operator[](SharedLibrary const& lib) -> Value&;
+
+        auto at(SharedLibrary const& lib) const -> Value const&;
+
+        auto begin() const -> decltype(values)::const_iterator;
+        auto end() const -> decltype(values)::const_iterator;
+
+        template<typename ...Args>
+        auto emplace(SharedLibrary const& lib, Args&& ...args) -> std::pair<typename decltype(values)::iterator, bool>
+        {
+            auto existing = find(lib);
+
+            if (existing != values.end())
+            {
+                return {existing, false};
+            }
+
+            values.emplace_back(
+                std::piecewise_construct,
+                std::forward_as_tuple(lib.get_handle()),
+                std::forward<Args>(args)...);
+
+            return {values.end() - 1, true};
+        }
+    };
+
+    LibraryMap<boost::program_options::options_description> module_options_desc;
+    LibraryMap<std::shared_ptr<Option>> mutable module_options;
     std::shared_ptr<Option> mutable options;
 };
 }

include/platform/mir/options/program_option.h

@@ -39,7 +39,7 @@ class ProgramOption : public Option
 
     void parse_environment(
         boost::program_options::options_description const& description,
-        char const* prefix);
+        std::function<std::string(std::string)> env_var_name_mapper);
 
     void parse_file(
         boost::program_options::options_description const& description,

src/include/server/mir/default_server_configuration.h

@@ -17,6 +17,7 @@
 #define MIR_DEFAULT_SERVER_CONFIGURATION_H_
 
 #include "mir/cached_ptr.h"
+#include "mir/options/option.h"
 #include "mir/server_configuration.h"
 #include "mir/shell/window_manager_builder.h"
 
@@ -137,7 +138,7 @@ class Logger;
 namespace options
 {
 class Option;
-class Configuration;
+class OptionsProvider;
 }
 
 namespace report
@@ -160,7 +161,7 @@ class DefaultServerConfiguration : public virtual ServerConfiguration
 {
 public:
     DefaultServerConfiguration(int argc, char const* argv[]);
-    explicit DefaultServerConfiguration(std::shared_ptr<options::Configuration> const& configuration_options);
+    explicit DefaultServerConfiguration(std::shared_ptr<options::OptionsProvider> const& configuration_options);
 
     /** @name DisplayServer dependencies
      * dependencies of DisplayServer on the rest of the Mir
@@ -347,6 +348,7 @@ class DefaultServerConfiguration : public virtual ServerConfiguration
 
 protected:
     std::shared_ptr<options::Option> the_options() const;
+    auto the_options_provider() const -> std::shared_ptr<options::OptionsProvider>;
     std::shared_ptr<input::DefaultInputDeviceHub>  the_default_input_device_hub();
     std::shared_ptr<graphics::DisplayConfigurationObserver> the_display_configuration_observer();
     std::shared_ptr<input::SeatObserver> the_seat_observer();
@@ -434,7 +436,7 @@ class DefaultServerConfiguration : public virtual ServerConfiguration
     std::shared_ptr<DecorationStrategy> decoration_strategy;
 
 private:
-    std::shared_ptr<options::Configuration> const configuration_options;
+    std::shared_ptr<options::OptionsProvider> const configuration_options;
     std::shared_ptr<input::EventFilter> default_filter;
     CachedPtr<ObserverMultiplexer<graphics::DisplayConfigurationObserver>>
         display_configuration_observer_multiplexer;