1 files changed, 59 insertions, 0 deletions
diff --git a/mesonbuild/wrap/__init__.py b/mesonbuild/wrap/__init__.py
new file mode 100644
index 0000000..653f42a
--- /dev/null
+++ b/mesonbuild/wrap/__init__.py
@@ -0,0 +1,59 @@
+from enum import Enum
+
+# Used for the --wrap-mode command-line argument
+#
+# Special wrap modes:
+#   nofallback: Don't download wraps for dependency() fallbacks
+#   nodownload: Don't download wraps for all subproject() calls
+#
+# subprojects are used for two purposes:
+# 1. To download and build dependencies by using .wrap
+#    files if they are not provided by the system. This is
+#    usually expressed via dependency(..., fallback: ...).
+# 2. To download and build 'copylibs' which are meant to be
+#    used by copying into your project. This is always done
+#    with an explicit subproject() call.
+#
+# --wrap-mode=nofallback will never do (1)
+# --wrap-mode=nodownload will do neither (1) nor (2)
+#
+# If you are building from a release tarball, you should be
+# able to safely use 'nodownload' since upstream is
+# expected to ship all required sources with the tarball.
+#
+# If you are building from a git repository, you will want
+# to use 'nofallback' so that any 'copylib' wraps will be
+# download as subprojects.
+#
+# --wrap-mode=forcefallback will ignore external dependencies,
+# even if they match the version requirements, and automatically
+# use the fallback if one was provided. This is useful for example
+# to make sure a project builds when using the fallbacks.
+#
+# Note that these options do not affect subprojects that
+# are git submodules since those are only usable in git
+# repositories, and you almost always want to download them.
+
+# This did _not_ work when inside the WrapMode class.
+# I don't know why. If you can fix this, patches welcome.
+string_to_value = {'default': 1,
+                   'nofallback': 2,
+                   'nodownload': 3,
+                   'forcefallback': 4,
+                   'nopromote': 5,
+                   }
+
+class WrapMode(Enum):
+    default = 1
+    nofallback = 2
+    nodownload = 3
+    forcefallback = 4
+    nopromote = 5
+
+    def __str__(self) -> str:
+        return self.name
+
+    @staticmethod
+    def from_string(mode_name: str) -> 'WrapMode':
+        g = string_to_value[mode_name]
+        return WrapMode(g)