tools/vcs_tag: Add support for reading .git

There is still no support for depfiles, so that would need to be
implemented. But it's a start

Author: dcbaker

src/tools/vcs_tag.cpp

@@ -2,19 +2,59 @@
 // Copyright © 2024 Intel Corporation
 
 #include "vcs_tag.hpp"
+#include "util/process.hpp"
 #include "util/utils.hpp"
 
 #include <cassert>
 #include <fstream>
 #include <iostream>
+#include <optional>
 #include <sstream>
+#include <vector>
 
 namespace Tools {
 
 namespace fs = std::filesystem;
 
+namespace {
+
+struct VCSData {
+    std::vector<std::string> command;
+    fs::path dep;
+};
+
+std::optional<VCSData> find_vcs(const fs::path & source_dir) {
+    // TODO: HG, Subversion, bazaar
+    const fs::path gitdir = source_dir / ".git";
+
+    if (fs::is_directory(gitdir)) {
+        return VCSData{
+            .command = {"git", "-C", source_dir, "describe", "--dirty=+", "--always"},
+            .dep = gitdir / "logs" / "HEAD", // TODO: This doesn't work for git work trees
+        };
+    }
+
+    return std::nullopt;
+}
+
+std::string get_version(const std::optional<VCSData> & vcs_o, std::string_view fallback) {
+    if (!vcs_o) {
+        return std::string{fallback};
+    }
+
+    const VCSData & vcs = vcs_o.value();
+    auto [rc, out, err] = Util::process(vcs.command);
+    if (rc != 0) {
+        throw std::runtime_error{"TODO: " + err};
+    }
+    out.pop_back();
+    return out;
+}
+
+} // namespace
+
 int generate_vcs_tag(const std::filesystem::path & infile, const std::filesystem::path & outfile,
-                     std::string_view version, std::string_view replacement,
+                     std::string_view fallback, std::string_view replacement,
                      const std::filesystem::path & source_dir) {
     // We assume that the infile exists and has been validated by the
     // transpiler, but for debug builds we can assert here.
@@ -23,6 +63,9 @@ int generate_vcs_tag(const std::filesystem::path & infile, const std::filesystem
     std::ifstream istream{infile};
     std::stringstream ostream{};
 
+    const std::optional<VCSData> vcs = find_vcs(source_dir);
+    const std::string version = get_version(vcs, fallback);
+
     for (std::string line; std::getline(istream, line);) {
         ostream << Util::replace(line, replacement, version) << std::endl;
     }
@@ -57,6 +100,8 @@ int generate_vcs_tag(const std::filesystem::path & infile, const std::filesystem
         }
     }
 
+    // TODO: emit depfile for git
+
     std::ofstream out{outfile};
     out << ostream.str();
     return 0;

tests/dsl/13 vcs_tag/compare.py

@@ -4,6 +4,7 @@
 
 from __future__ import annotations
 import argparse
+import difflib
 import filecmp
 import sys
 import typing as T
@@ -20,8 +21,14 @@ def main() -> int:
     parser.add_argument('expected')
     args: Arguments = parser.parse_args()
 
-    same = filecmp.cmp(args.result, args.expected)
-    return 0 if same else 1
+    if filecmp.cmp(args.result, args.expected):
+        return 0
+
+    with open(args.result, 'r') as fr, open(args.expected, 'r') as fe:
+        for line in difflib.ndiff(fe.readlines(), fr.readlines()):
+            print(line, file=sys.stderr, end='')
+
+    return 1
 
 
 if __name__ == "__main__":

tests/dsl/14 vcs_tag git/basic.in

@@ -0,0 +1,2 @@
+This is a @VCS_TAG@ and @VCS_TAG@
+    @VCS_TAG@ @@VCS_TAG@ @VCS_TAG

tests/dsl/14 vcs_tag git/compare.py

@@ -0,0 +1,57 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: Apache-2.0
+# Copyright © 2024 Intel Corporation
+
+from __future__ import annotations
+import argparse
+import difflib
+import os
+import subprocess
+import sys
+import typing as T
+
+if T.TYPE_CHECKING:
+    class Arguments(T.Protocol):
+        result: str
+        template: str
+
+
+def main() -> int:
+    parser = argparse.ArgumentParser()
+    parser.add_argument('result')
+    parser.add_argument('template')
+    args: Arguments = parser.parse_args()
+
+    with open(args.result, 'r') as f:
+        got = f.read()
+
+    with open(args.template, 'r') as f:
+        tmpl = f.read()
+
+    # TODO: Cheating a bit here because Meson++ doesn't have the meson object
+    # implemented yet.
+    source_dir = os.path.dirname(args.template)
+
+    v = subprocess.run(
+        ["git", "-C", source_dir, "describe", "--dirty=+", "--always"],
+        stdout=subprocess.PIPE,
+        stderr=subprocess.PIPE,
+        universal_newlines=True,
+    )
+    if v.returncode != 0:
+        print(v.stderr, file=sys.stderr)
+        return 2
+    ever = v.stdout.strip()
+    expected = tmpl.replace('@VCS_TAG@', ever)
+
+    if got == expected:
+        return 0
+
+    for line in difflib.ndiff(got.splitlines(), expected.splitlines()):
+        print(line, file=sys.stderr)
+
+    return 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())

tests/dsl/14 vcs_tag git/meson.build

@@ -0,0 +1,14 @@
+# SPDX-License-Identifier: Apache-2.0
+# Copyright © 2024 Intel Corporation
+
+project(
+  'vcs_tag (git) test',
+  version: '1.0.0',
+)
+
+python = find_program('python')
+tester = files('compare.py')
+
+# TODO: this will not work correctly whenever we implement support for VCs.
+x = vcs_tag(input: 'basic.in', output: 'basic.out')
+test('git', python, args: [tester, x, files('basic.in')])

tests/dsl/14 vcs_tag git/setup.sh

@@ -0,0 +1,11 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+SOURCEDIR="${1}"
+
+pushd "${SOURCEDIR}"
+git init .
+git add .
+git commit -a -m "test commit"
+git tag 1
+popd

tests/dsl/14 vcs_tag git/teardown.sh

@@ -0,0 +1,6 @@
+#!/usr/bin/env bash
+set -euxo pipefail
+
+SOURCEDIR="${1}"
+
+rm -rf "${SOURCEDIR}/.git"

tests/meson.build

@@ -18,6 +18,7 @@ test_cases = {
     '11 test types',
     '12 add arguments',
     '13 vcs_tag',
+    '14 vcs_tag git',
   ],
 }