convert into a proper Python module

Sem-Ver: api-break

1 files changed, 68 insertions, 0 deletions

diff --git a/git_deps/gitutils.py b/git_deps/gitutils.py
new file mode 100644
index 0000000..f5d8281
--- /dev/null
+++ b/git_deps/gitutils.py
@@ -0,0 +1,68 @@
+import re
+import subprocess
+
+
+class GitUtils(object):
+    @classmethod
+    def abbreviate_sha1(cls, sha1):
+        """Uniquely abbreviates the given SHA1."""
+
+        # For now we invoke git-rev-parse(1), but hopefully eventually
+        # we will be able to do this via pygit2.
+        cmd = ['git', 'rev-parse', '--short', sha1]
+        # cls.logger.debug(" ".join(cmd))
+        out = subprocess.check_output(cmd).strip()
+        # cls.logger.debug(out)
+        return out
+
+    @classmethod
+    def describe(cls, sha1):
+        """Returns a human-readable representation of the given SHA1."""
+
+        # For now we invoke git-describe(1), but eventually we will be
+        # able to do this via pygit2, since libgit2 already provides
+        # an API for this:
+        #   https://github.com/libgit2/pygit2/pull/459#issuecomment-68866929
+        #   https://github.com/libgit2/libgit2/pull/2592
+        cmd = [
+            'git', 'describe',
+            '--all',       # look for tags and branches
+            '--long',      # remotes/github/master-0-g2b6d591
+            # '--contains',
+            # '--abbrev',
+            sha1
+        ]
+        # cls.logger.debug(" ".join(cmd))
+        out = None
+        try:
+            out = subprocess.check_output(cmd, stderr=subprocess.STDOUT)
+        except subprocess.CalledProcessError as e:
+            if e.output.find('No tags can describe') != -1:
+                return ''
+            raise
+
+        out = out.strip()
+        out = re.sub(r'^(heads|tags|remotes)/', '', out)
+        # We already have the abbreviated SHA1 from abbreviate_sha1()
+        out = re.sub(r'-g[0-9a-f]{7,}$', '', out)
+        # cls.logger.debug(out)
+        return out
+
+    @classmethod
+    def refs_to(cls, sha1, repo):
+        """Returns all refs pointing to the given SHA1."""
+        matching = []
+        for refname in repo.listall_references():
+            symref = repo.lookup_reference(refname)
+            dref = symref.resolve()
+            oid = dref.target
+            commit = repo.get(oid)
+            if commit.hex == sha1:
+                matching.append(symref.shorthand)
+
+        return matching
+
+    @classmethod
+    def rev_list(cls, rev_range):
+        cmd = ['git', 'rev-list', rev_range]
+        return subprocess.check_output(cmd).strip().split('\n')