_platform: make picklable, no nested methods

Make the _platform implementations pickable by moving the nested
_setup_*_sandbox methods up into their enclosing classes.

3 files changed, 53 insertions, 49 deletions

diff --git a/src/buildstream/_platform/darwin.py b/src/buildstream/_platform/darwin.py
index e8c1ffaf3..f23535373 100644
--- a/src/buildstream/_platform/darwin.py
+++ b/src/buildstream/_platform/darwin.py
@@ -53,16 +53,18 @@ class Darwin(Platform):
         soft_limit = min(max(self.OPEN_MAX, old_soft_limit), hard_limit)
         resource.setrlimit(resource.RLIMIT_NOFILE, (soft_limit, hard_limit))
 
-    def _setup_dummy_sandbox(self):
-        def _check_dummy_sandbox_config(config):
-            return True
-        self.check_sandbox_config = _check_dummy_sandbox_config
+    @staticmethod
+    def _check_dummy_sandbox_config(config):
+        return True
 
-        def _create_dummy_sandbox(*args, **kwargs):
-            kwargs['dummy_reason'] = \
-                "OSXFUSE is not supported and there are no supported sandbox " + \
-                "technologies for MacOS at this time"
-            return SandboxDummy(*args, **kwargs)
-        self.create_sandbox = _create_dummy_sandbox
+    @staticmethod
+    def _create_dummy_sandbox(*args, **kwargs):
+        kwargs['dummy_reason'] = \
+            "OSXFUSE is not supported and there are no supported sandbox " + \
+            "technologies for MacOS at this time"
+        return SandboxDummy(*args, **kwargs)
 
+    def _setup_dummy_sandbox(self):
+        self.check_sandbox_config = Darwin._check_dummy_sandbox_config
+        self.create_sandbox = Darwin._create_dummy_sandbox
         return True
diff --git a/src/buildstream/_platform/fallback.py b/src/buildstream/_platform/fallback.py
index 39669e0c2..4f7ff8086 100644
--- a/src/buildstream/_platform/fallback.py
+++ b/src/buildstream/_platform/fallback.py
@@ -21,17 +21,17 @@ from .platform import Platform
 
 class Fallback(Platform):
 
-    def _setup_dummy_sandbox(self):
-        def _check_dummy_sandbox_config(config):
-            return True
-        self.check_sandbox_config = _check_dummy_sandbox_config
+    def _check_dummy_sandbox_config(self, config):
+        return True
 
-        def _create_dummy_sandbox(*args, **kwargs):
-            kwargs['dummy_reason'] = \
-                ("FallBack platform only implements dummy sandbox, "
-                 "Buildstream may be having issues correctly detecting your platform, platform "
-                 "can be forced with BST_FORCE_BACKEND")
-            return SandboxDummy(*args, **kwargs)
-        self.create_sandbox = _create_dummy_sandbox
+    def _create_dummy_sandbox(self, *args, **kwargs):
+        kwargs['dummy_reason'] = \
+            ("FallBack platform only implements dummy sandbox, "
+             "Buildstream may be having issues correctly detecting your platform, "
+             "platform can be forced with BST_FORCE_BACKEND")
+        return SandboxDummy(*args, **kwargs)
 
+    def _setup_dummy_sandbox(self):
+        self.check_sandbox_config = self._check_dummy_sandbox_config
+        self.create_sandbox = self._create_dummy_sandbox
         return True
diff --git a/src/buildstream/_platform/linux.py b/src/buildstream/_platform/linux.py
index 3d85fdf34..b69dd456e 100644
--- a/src/buildstream/_platform/linux.py
+++ b/src/buildstream/_platform/linux.py
@@ -67,19 +67,28 @@ class Linux(Platform):
     #              Private Methods                 #
     ################################################
 
-    def _setup_dummy_sandbox(self):
+    @staticmethod
+    def _check_dummy_sandbox_config(config):
+        return True
+
+    def _create_dummy_sandbox(self, *args, **kwargs):
         dummy_reasons = " and ".join(self.dummy_reasons)
+        kwargs['dummy_reason'] = dummy_reasons
+        return SandboxDummy(*args, **kwargs)
 
-        def _check_dummy_sandbox_config(config):
-            return True
-        self.check_sandbox_config = _check_dummy_sandbox_config
+    def _setup_dummy_sandbox(self):
+        self.check_sandbox_config = Linux._check_dummy_sandbox_config
+        self.create_sandbox = self._create_dummy_sandbox
+        return True
 
-        def _create_dummy_sandbox(*args, **kwargs):
-            kwargs['dummy_reason'] = dummy_reasons
-            return SandboxDummy(*args, **kwargs)
-        self.create_sandbox = _create_dummy_sandbox
+    def _check_sandbox_config_bwrap(self, config):
+        from ..sandbox._sandboxbwrap import SandboxBwrap
+        return SandboxBwrap.check_sandbox_config(self, config)
 
-        return True
+    def _create_bwrap_sandbox(self, *args, **kwargs):
+        from ..sandbox._sandboxbwrap import SandboxBwrap
+        kwargs['linux32'] = self.linux32
+        return SandboxBwrap(*args, **kwargs)
 
     def _setup_bwrap_sandbox(self):
         from ..sandbox._sandboxbwrap import SandboxBwrap
@@ -90,29 +99,22 @@ class Linux(Platform):
 
         SandboxBwrap._have_good_bwrap = None
         self._check_sandbox(SandboxBwrap)
+        self.check_sandbox_config = self._check_sandbox_config_bwrap
+        self.create_sandbox = self._create_bwrap_sandbox
+        return True
 
-        def _check_sandbox_config_bwrap(config):
-            return SandboxBwrap.check_sandbox_config(self, config)
-        self.check_sandbox_config = _check_sandbox_config_bwrap
-
-        def _create_bwrap_sandbox(*args, **kwargs):
-            kwargs['linux32'] = self.linux32
-            return SandboxBwrap(*args, **kwargs)
-        self.create_sandbox = _create_bwrap_sandbox
+    def _check_sandbox_config_chroot(self, config):
+        from ..sandbox._sandboxchroot import SandboxChroot
+        return SandboxChroot.check_sandbox_config(self, config)
 
-        return True
+    @staticmethod
+    def _create_chroot_sandbox(*args, **kwargs):
+        from ..sandbox._sandboxchroot import SandboxChroot
+        return SandboxChroot(*args, **kwargs)
 
     def _setup_chroot_sandbox(self):
         from ..sandbox._sandboxchroot import SandboxChroot
-
         self._check_sandbox(SandboxChroot)
-
-        def _check_sandbox_config_chroot(config):
-            return SandboxChroot.check_sandbox_config(self, config)
-        self.check_sandbox_config = _check_sandbox_config_chroot
-
-        def _create_chroot_sandbox(*args, **kwargs):
-            return SandboxChroot(*args, **kwargs)
-        self.create_sandbox = _create_chroot_sandbox
-
+        self.check_sandbox_config = self._check_sandbox_config_chroot
+        self.create_sandbox = Linux._create_chroot_sandbox
         return True