cargo/version: add a function to convert cargo versioning to meson

1 files changed, 96 insertions, 0 deletions

diff --git a/mesonbuild/cargo/version.py b/mesonbuild/cargo/version.py
new file mode 100644
index 0000000..cb09a00
--- /dev/null
+++ b/mesonbuild/cargo/version.py
@@ -0,0 +1,96 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright © 2022-2023 Intel Corporation
+
+"""Convert Cargo versions into Meson compatible ones."""
+
+from __future__ import annotations
+import typing as T
+
+
+def convert(cargo_ver: str) -> T.List[str]:
+    """Convert a Cargo compatible version into a Meson compatible one.
+
+    :param cargo_ver: The version, as Cargo specifies
+    :return: A list of version constraints, as Meson understands them
+    """
+    # Cleanup, just for safety
+    cargo_ver = cargo_ver.strip()
+    cargo_vers = [c.strip() for c in cargo_ver.split(',')]
+
+    out: T.List[str] = []
+
+    for ver in cargo_vers:
+        # This covers >= and =< as well
+        # https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#comparison-requirements
+        if ver.startswith(('>', '<', '=')):
+            out.append(ver)
+
+        elif ver.startswith('~'):
+            # Rust has these tilde requirements, which means that it is >= to
+            # the version, but less than the next version
+            # https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#tilde-requirements
+            # we convert those into a pair of constraints
+            v = ver[1:].split('.')
+            out.append(f'>= {".".join(v)}')
+            if len(v) == 3:
+                out.append(f'< {v[0]}.{int(v[1]) + 1}.0')
+            elif len(v) == 2:
+                out.append(f'< {v[0]}.{int(v[1]) + 1}')
+            else:
+                out.append(f'< {int(v[0]) + 1}')
+
+        elif '*' in ver:
+            # Rust has astrisk requirements,, which are like 1.* == ~1
+            # https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#wildcard-requirements
+            v = ver.split('.')[:-1]
+            if v:
+                out.append(f'>= {".".join(v)}')
+            if len(v) == 2:
+                out.append(f'< {v[0]}.{int(v[1]) + 1}')
+            elif len(v) == 1:
+                out.append(f'< {int(v[0]) + 1}')
+
+        else:
+            # a Caret version is equivalent to the default strategy
+            # https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#caret-requirements
+            if ver.startswith('^'):
+                ver = ver[1:]
+
+            # If there is no qualifier, then it means this or the next non-zero version
+            # That means that if this is `1.1.0``, then we need `>= 1.1.0` && `< 2.0.0`
+            # Or if we have `0.1.0`, then we need `>= 0.1.0` && `< 0.2.0`
+            # Or if we have `0.1`, then we need `>= 0.1.0` && `< 0.2.0`
+            # Or if we have `0.0.0`, then we need `< 1.0.0`
+            # Or if we have `0.0`, then we need `< 1.0.0`
+            # Or if we have `0`, then we need `< 1.0.0`
+            # Or if we have `0.0.3`, then we need `>= 0.0.3` && `< 0.0.4`
+            # https://doc.rust-lang.org/cargo/reference/specifying-dependencies.html#specifying-dependencies-from-cratesio
+            #
+            # this works much like the ~ versions, but in reverse. Tilde starts
+            # at the patch version and works up, to the major version, while
+            # bare numbers start at the major version and work down to the patch
+            # version
+            vers = ver.split('.')
+            min_: T.List[str] = []
+            max_: T.List[str] = []
+            bumped = False
+            for v_ in vers:
+                if v_ != '0' and not bumped:
+                    min_.append(v_)
+                    max_.append(str(int(v_) + 1))
+                    bumped = True
+                else:
+                    if not (bumped and v_ == '0'):
+                        min_.append(v_)
+                    if not bumped:
+                        max_.append('0')
+
+            # If there is no minimum, don't emit one
+            if set(min_) != {'0'}:
+                out.append('>= {}'.format('.'.join(min_)))
+            if set(max_) != {'0'}:
+                out.append('< {}'.format('.'.join(max_)))
+            else:
+                out.append('< 1')
+
+    return out