Merge lp:~alan-griffiths/mir/configurable-graphicsplatform into lp:~mir-team/mir/trunk

[Alan Griffiths]

config: allow graphics platform library to be selected by command-line/config

config: allow graphics platform library to be selected by command-line/config

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FAILED: Continuous integration, rev:766
http://jenkins.qa.ubuntu.com/job/mir-ci/793/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-android-saucy-i386-build/996
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-saucy-amd64-build/881
    FAILURE: http://jenkins.qa.ubuntu.com/job/mir-saucy-amd64-ci/31/console
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-vm-ci-build/./distribution=quantal,flavor=amd64/469

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review: Needs Fixing (continuous-integration)

[PS Jenkins bot (ps-jenkins)]

PASSED: Continuous integration, rev:767
http://jenkins.qa.ubuntu.com/job/mir-ci/794/
Executed test runs:
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-android-saucy-i386-build/997
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-clang-saucy-amd64-build/882
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-saucy-amd64-ci/32
        deb: http://jenkins.qa.ubuntu.com/job/mir-saucy-amd64-ci/32/artifact/work/output/*zip*/output.zip
    SUCCESS: http://jenkins.qa.ubuntu.com/job/mir-vm-ci-build/./distribution=quantal,flavor=amd64/470

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review: Approve (continuous-integration)

[Daniel van Vugt (vanvugt)]

Interesting approach and probably a good first step.

Though I suspect the final "driver model" needs to be implementable with a pure C API. So maybe it's dangerous to establish a precedent that we load C++ code dynamically. We'd be establishing a C++ ABI when we don't want one, in the end.

[Robert Carr (robertcarr)]

LGTM. I agree that the "driver model" needs a C API, though I think this is more about correctly supporting mir-on-mir, mir-on-x, etc. Either way

review: Approve

[Kevin DuBois (kdub)]

lgtm too

review: Approve

=== modified file 'src/server/default_server_configuration.cpp'
--- src/server/default_server_configuration.cpp	2013-06-21 16:21:33 +0000
+++ src/server/default_server_configuration.cpp	2013-06-21 16:21:33 +0000
@@ -69,6 +69,8 @@
 #include "mir/time/high_resolution_clock.h"
 #include "mir/default_configuration.h"
 
+#include <map>
+
 namespace mc = mir::compositor;
 namespace me = mir::events;
 namespace geom = mir::geometry;
@@ -83,6 +85,7 @@
 namespace
 {
 std::initializer_list<std::shared_ptr<mi::EventFilter> const> empty_filter_list{};
+mir::SharedLibrary const* load_library(std::string const& libname);
 }
 
 namespace
@@ -157,6 +160,9 @@
 char const* const log_opt_value = "log";
 char const* const lttng_opt_value = "lttng";
 
+char const* const platform_graphics_lib = "platform-graphics-lib";
+char const* const default_platform_graphics_lib = "libmirplatformgraphics.so";
+
 void parse_arguments(
     boost::program_options::options_description desc,
     std::shared_ptr<mir::options::ProgramOption> const& options,
@@ -213,6 +219,8 @@
     add_options()
         ("file,f", po::value<std::string>(),
             "Socket filename")
+        (platform_graphics_lib, po::value<std::string>(),
+            "Library to use for platform graphics support [default=libmirplatformgraphics.so")
         ("enable-input,i", po::value<bool>(),
             "Enable input. [bool:default=true]")
         (display_report_opt, po::value<std::string>(),
@@ -297,8 +305,8 @@
     return graphics_platform(
         [this]()
         {
-            static SharedLibrary libmirplatformgraphics("libmirplatformgraphics.so");
-            static auto create_platform = libmirplatformgraphics.load_function<mg::CreatePlatform>("create_platform");
+            auto graphics_lib = load_library(the_options()->get(platform_graphics_lib, default_platform_graphics_lib));
+            auto create_platform = graphics_lib->load_function<mg::CreatePlatform>("create_platform");
             return create_platform(the_options(), the_display_report());
         });
 }
@@ -729,3 +737,22 @@
             return std::make_shared<mir::AsioMainLoop>();
         });
 }
+
+namespace
+{
+mir::SharedLibrary const* load_library(std::string const& libname)
+{
+    // There's no point in loading twice, and it isn't safe to unload...
+    static std::map<std::string, std::shared_ptr<mir::SharedLibrary>> libraries_cache;
+
+    if (auto& ptr = libraries_cache[libname])
+    {
+        return ptr.get();
+    }
+    else
+    {
+        ptr = std::make_shared<mir::SharedLibrary>(libname);
+        return ptr.get();
+    }
+}
+}