pkgs.profpatsch: add git-commit-index tools

A set of utilities to generate and query a git commit index, which is
a database that knows which revs (that is: commits) are in which git
repository. That way we can query for the project that contains a
commit and show them, e.g. with xdg-open.

1 files changed, 102 insertions, 0 deletions

diff --git a/pkgs/profpatsch/git-commit-index/lib.sh b/pkgs/profpatsch/git-commit-index/lib.sh
new file mode 100644
index 00000000..229eec1e
--- /dev/null
+++ b/pkgs/profpatsch/git-commit-index/lib.sh
@@ -0,0 +1,102 @@
+set -euo pipefail
+
+# nix-shell -p cdb --run 'bash -c \'source ~/tmp/gitcdb.sh; for r in $(findRepos ~/kot); do genIndex . "$r"; done\''
+
+findRepos () {
+    find "$1" -type d -name ".git"
+    # TODO check each repo is actually git repo
+}
+
+genIndex () {
+    local indexDir=$(realpath -- "$1")
+    local path=$(realpath -- "$2")
+    if [ ! -d "$indexDir" ]; then
+        echo "index directory does not exist: $indexDir"
+        exit 111
+    fi
+    # TODO: multimap failure
+    #
+    local filename="$indexDir/$(echo $path | sed -e 's|_|__|g' -e 's|/|_|g')"
+    local pathLength=$(echo "$path" | wc --bytes | tr -d '\n')
+    (pushd "$path" > /dev/null \
+            && ( git log --all --format="format:%H" \
+                     | sed -e "s/^\(.*\)$/+40,0:\1->/" \
+               ; echo \
+               ; echo "+8,${pathLength}:git-path->${path}" \
+               ; echo; echo \
+               ) \
+            | cdbmake "$filename" "$filename.tmp" \
+    )
+}
+
+query () {
+    local indexDir=$(realpath -- "$1")
+    local key="$2"
+
+    local found=0
+    local result=
+
+    # TODO make this parallel (and switch away from bash)
+    for f in "$indexDir"/*; do
+
+        set +e
+        # don't need result because empty string
+        <"$f" cdbget "$key" >/dev/null
+        local ret=$?
+        set -e
+
+        case $ret in
+            0)
+                # TODO: back
+                found=1
+
+                set +e
+                # now find original path
+                local origDotGit=$(<"$f" cdbget "git-path")
+                local retGitPath=$?
+                set -e
+
+                case $retGitPath in
+                    0)
+                        :
+                        ;;
+                    100)
+                        echo "shouldn’t happen; git-path was not in $f"
+                        exit 127
+                        ;;
+                    111)
+                        echo "db error in $f"
+                        exit 111
+                        ;;
+                    *)
+                        echo "shouldn’t happen; exitcode was $ret"
+                        exit 127
+                        ;;
+                esac
+
+                # return workspace file
+                result=$(dirname "$origDotGit")
+                break
+                ;;
+            100)
+                # not found
+                :
+                ;;
+            111)
+                echo "db error in $f"
+                exit 111
+                ;;
+            *)
+                echo "shouldn’t happen; exitcode was $ret"
+                exit 127
+                ;;
+        esac
+    done
+
+    if [ $found -eq 0 ]; then
+        exit 100
+    else
+        echo "$result"
+        exit 0
+    fi
+}