cargo: create dataclasses for Cargo.lock

Start introducing a new simpler API for conversion of TypedDicts to
dataclasses, and use it already for Cargo.lock.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/mesonbuild/cargo/version.py b/mesonbuild/cargo/version.py
index cde7a83a3..51ce79b04 100644
--- a/mesonbuild/cargo/version.py
+++ b/mesonbuild/cargo/version.py
@@ -7,6 +7,18 @@ from __future__ import annotations
 import typing as T
 
 
+def api(version: str) -> str:
+    # x.y.z -> x
+    # 0.x.y -> 0.x
+    # 0.0.x -> 0
+    vers = version.split('.')
+    if int(vers[0]) != 0:
+        return vers[0]
+    elif len(vers) >= 2 and int(vers[1]) != 0:
+        return f'0.{vers[1]}'
+    return '0'
+
+
 def convert(cargo_ver: str) -> T.List[str]:
     """Convert a Cargo compatible version into a Meson compatible one.