Factor out loading & running of DSOs

mojo/shell/dynamic_service_runner.cc

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "mojo/shell/dynamic_service_runner.h"
+
+#include "base/files/file_path.h"
+#include "base/logging.h"
+#include "mojo/public/platform/native/gles2_impl_chromium_sync_point_thunks.h"
+#include "mojo/public/platform/native/gles2_impl_chromium_texture_mailbox_thunks.h"
+#include "mojo/public/platform/native/gles2_impl_thunks.h"
+#include "mojo/public/platform/native/gles2_thunks.h"
+#include "mojo/public/platform/native/system_thunks.h"
+
+namespace mojo {
+namespace shell {
+
+namespace {
+
+template <typename Thunks>
+bool SetThunks(Thunks (*make_thunks)(),
+               const char* function_name,
+               base::NativeLibrary library) {
+  typedef size_t (*SetThunksFn)(const Thunks* thunks);
+  SetThunksFn set_thunks =
+      reinterpret_cast<SetThunksFn>(base::GetFunctionPointerFromNativeLibrary(
+          library, function_name));
+  if (!set_thunks)
+    return false;
+  Thunks thunks = make_thunks();
+  size_t expected_size = set_thunks(&thunks);
+  if (expected_size > sizeof(Thunks)) {
+    LOG(ERROR) << "Invalid app library: expected " << function_name
+               << " to return thunks of size: " << expected_size;
+    return false;
+  }
+  return true;
+}
+
+}  // namespace
+
+base::NativeLibrary DynamicServiceRunner::LoadAndRunService(
+    const base::FilePath& app_path,
+    ScopedMessagePipeHandle service_handle) {
+#if defined(COMPONENT_BUILD)
+  NOTREACHED() << "Only static builds are supported";
+  return nullptr;
+#endif
+
+  DVLOG(2) << "Loading/running Mojo app in process from library: "
+           << app_path.value();
+  base::NativeLibraryLoadError error;
+  base::NativeLibrary app_library = base::LoadNativeLibrary(app_path, &error);
+  do {
+    if (!app_library) {
+      LOG(ERROR) << "Failed to load app library (error: " << error.ToString()
+                 << ")";
+      break;
+    }
+    // Go shared library support requires us to initialize the runtime before we
+    // start running any go code. This is a temporary patch.
+    typedef void (*InitGoRuntimeFn)();
+    InitGoRuntimeFn init_go_runtime = reinterpret_cast<InitGoRuntimeFn>(
+        base::GetFunctionPointerFromNativeLibrary(
+            app_library, "InitGoRuntime"));
+    if (init_go_runtime) {
+      DVLOG(2) << "InitGoRuntime: Initializing Go Runtime found in app";
+      init_go_runtime();
+    }
+
+    if (!SetThunks(&MojoMakeSystemThunks, "MojoSetSystemThunks", app_library)) {
+      LOG(ERROR) << app_path.value() << " MojoSetSystemThunks not found";
+      break;
+    }
+
+    if (SetThunks(&MojoMakeGLES2ControlThunks,
+                  "MojoSetGLES2ControlThunks",
+                  app_library)) {
+      // If we have the control thunks, we should also have the GLES2
+      // implementation thunks.
+      if (!SetThunks(&MojoMakeGLES2ImplThunks,
+                     "MojoSetGLES2ImplThunks",
+                     app_library)) {
+        LOG(ERROR) << app_path.value()
+                   << " has MojoSetGLES2ControlThunks, "
+                      "but doesn't have MojoSetGLES2ImplThunks.";
+        break;
+      }
+
+      // If the application is using GLES2 extension points, register those
+      // thunks. Applications may use or not use any of these, so don't warn if
+      // they are missing.
+      SetThunks(MojoMakeGLES2ImplChromiumTextureMailboxThunks,
+                "MojoSetGLES2ImplChromiumTextureMailboxThunks",
+                app_library);
+      SetThunks(MojoMakeGLES2ImplChromiumSyncPointThunks,
+                "MojoSetGLES2ImplChromiumSyncPointThunks",
+                app_library);
+    }
+    // Unlike system thunks, we don't warn on a lack of GLES2 thunks because
+    // not everything is a visual app.
+
+    typedef MojoResult (*MojoMainFunction)(MojoHandle);
+    MojoMainFunction main_function = reinterpret_cast<MojoMainFunction>(
+        base::GetFunctionPointerFromNativeLibrary(app_library, "MojoMain"));
+    if (!main_function) {
+      LOG(ERROR) << app_path.value() << " MojoMain not found";
+      break;
+    }
+    // |MojoMain()| takes ownership of the service handle.
+    MojoResult result = main_function(service_handle.release().value());
+    if (result < MOJO_RESULT_OK) {
+      LOG(ERROR) << app_path.value()
+                 << " MojoMain returned error(" << result << ")";
+    }
+  } while (false);
+
+  return app_library;
+}
+
+}  // namespace shell
+}  // namespace mojo