Minimal libcloudproviders support #7209

- Add it as an optional dependency for linux builds,
  controlled by WITH_LIBCLOUDPROVIDERS, which is enabled automatically
  if the dependencies are available. Note that >=0.3.0 is required.

- Add code to export sync folders through the library and to add a
  minimal "Settings..." menu action.

- Set up cloud provider registration by installing a file into a
  path like /usr/share/cloud-providers/.

- DBus name and path are derived from APPLICATION_REV_DOMAIN by default
  and may be overridden with APPLICATION_CLOUDPROVIDERS_DBUS_NAME and
  APPLICATION_CLOUDPROVIDERS_DBUS_PATH if necessary.

1 files changed, 42 insertions, 0 deletions

diff --git a/cmake/modules/FindLibcloudproviders.cmake b/cmake/modules/FindLibcloudproviders.cmake
new file mode 100644
index 000000000..39edb200c
--- /dev/null
+++ b/cmake/modules/FindLibcloudproviders.cmake
@@ -0,0 +1,42 @@
+# (c) 2019 Copyright ownCloud GmbH
+# Redistribution and use is allowed according to the terms of the BSD license.
+# For details see the accompanying COPYING* file.
+
+find_path(LIBCLOUDPROVIDERS_INCLUDE_DIR
+            NAMES
+              cloudprovidersaccountexporter.h
+              cloudprovidersproviderexporter.h
+            PATH_SUFFIXES
+              cloudproviders
+            )
+
+find_library(LIBCLOUDPROVIDERS_LIBRARY
+            NAMES
+              cloudproviders
+            PATHS
+              /usr/lib
+              /usr/lib/${CMAKE_ARCH_TRIPLET}
+              /usr/local/lib
+              ${CMAKE_LIBRARY_PATH}
+              ${CMAKE_INSTALL_PREFIX}/lib
+            )
+
+# Using version <0.3.0 would lead to crashes during runtime when accounts are unexported.
+get_filename_component(LIBCLOUDPROVIDERS_LIBRARY_REALPATH ${LIBCLOUDPROVIDERS_LIBRARY} REALPATH)
+if(${LIBCLOUDPROVIDERS_LIBRARY_REALPATH} MATCHES "\.([0-9]*)\.([0-9]*)\.([0-9]*)$")
+    if ((${CMAKE_MATCH_1} EQUAL 0) AND (${CMAKE_MATCH_2} LESS 3))
+        message("libcloudproviders version is older than 0.3.0, not enabling it")
+        set(LIBCLOUDPROVIDERS_LIBRARY "")
+    endif()
+else()
+    message("Can't determine libcloudproviders version, not enabling it")
+    set(LIBCLOUDPROVIDERS_LIBRARY "")
+endif()
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(
+        LIBCLOUDPROVIDERS
+	DEFAULT_MSG
+	LIBCLOUDPROVIDERS_LIBRARY LIBCLOUDPROVIDERS_INCLUDE_DIR)
+
+mark_as_advanced(LIBCLOUDPROVIDERS_INCLUDE_DIR LIBCLOUDPROVIDERS_LIBRARY)