lib/git: add irc-announce

2 files changed, 139 insertions, 4 deletions

diff --git a/lib/default.nix b/lib/default.nix
index 27cf0e2..164a6a1 100644
--- a/lib/default.nix
+++ b/lib/default.nix
@@ -1,4 +1,4 @@
-{ lib, ... }:
+{ lib, pkgs, ... }:
 
 with builtins;
 
@@ -11,6 +11,7 @@ rec {
     lib = lib // {
       inherit addNames;
     };
+    inherit pkgs;
   };
 
   addName = name: set:
diff --git a/lib/git.nix b/lib/git.nix
index 5916cf8..b28d894 100644
--- a/lib/git.nix
+++ b/lib/git.nix
@@ -1,7 +1,7 @@
-{ lib, ... }:
+{ lib, pkgs, ... }:
 
 let
-  inherit (lib) addNames;
+  inherit (lib) addNames escapeShellArg makeSearchPath;
 
   commands = addNames {
     git-receive-pack = {};
@@ -37,5 +37,139 @@ let
     master = "refs/heads/master";
     all-heads = "refs/heads/*";
   };
+
+  irc-announce-script = pkgs.writeScript "irc-announce-script" ''
+    #! /bin/sh
+    set -euf
+
+    export PATH=${makeSearchPath "bin" (with pkgs; [
+      coreutils
+      gawk
+      gnused
+      netcat
+    ])}
+
+    IRC_SERVER="$1"
+    IRC_PORT="$2"
+    IRC_NICK="$3"
+    IRC_CHANNEL="$4"
+    message=$5
+
+    export IRC_CHANNEL # for privmsg_cat
+
+    # echo2 and cat2 are used output to both, stdout and stderr
+    # This is used to see what we send to the irc server. (debug output)
+    echo2() { echo "$*"; echo "$*" >&2; }
+    cat2() { tee /dev/stderr; }
+
+    # privmsg_cat transforms stdin to a privmsg
+    privmsg_cat() { awk '{ print "PRIVMSG "ENVIRON["IRC_CHANNEL"]" :"$0 }'; }
+
+    # ircin is used to feed the output of netcat back to the "irc client"
+    # so we can implement expect-like behavior with sed^_^
+    # XXX mkselfdestructingtmpfifo would be nice instead of this cruft
+    tmpdir="$(mktemp -d irc-announce_XXXXXXXX)"
+    cd "$tmpdir"
+    mkfifo ircin
+    trap "
+      rm ircin
+      cd '$OLDPWD'
+      rmdir '$tmpdir'
+      trap - EXIT INT QUIT
+    " EXIT INT QUIT
+
+    {
+      echo2 "USER $LOGNAME 0 * :$LOGNAME@$(hostname)"
+      echo2 "NICK $IRC_NICK"
+
+      # wait for MODE message
+      sed -n '/^:[^ ]* MODE /q'
+
+      echo2 "JOIN $IRC_CHANNEL"
+
+      printf '%s' "$message" \
+        | privmsg_cat \
+        | cat2
+
+      echo2 "PART $IRC_CHANNEL"
+
+      # wait for PART confirmation
+      sed -n '/:'"$IRC_NICK"'![^ ]* PART /q'
+
+      echo2 'QUIT :Gone to have lunch'
+    } < ircin \
+      | nc "$IRC_SERVER" "$IRC_PORT" | tee -a ircin
+  '';
+
+  hooks = {
+    # TODO make this a package?
+    irc-announce = { nick, channel, server, port ? 6667 }: ''
+      #! /bin/sh
+      set -euf
+
+      export PATH=${makeSearchPath "bin" (with pkgs; [
+        coreutils
+        git
+        gnused
+      ])}
+
+      nick=${escapeShellArg nick}
+      channel=${escapeShellArg channel}
+      server=${escapeShellArg server}
+      port=${toString port}
+
+      empty=0000000000000000000000000000000000000000
+
+      unset message
+      while read oldrev newrev ref; do
+
+        if [ $oldrev = $empty ]; then
+          receive_mode=create
+        elif [ $newrev = $empty ]; then
+          receive_mode=delete
+        elif [ "$(git merge-base $oldrev $newrev)" = $oldrev ]; then
+          receive_mode=fast-forward
+        else
+          receive_mode=non-fast-forward
+        fi
+
+        h=$(echo $ref | sed 's:^refs/heads/::')
+
+        # empty_tree=$(git hash-object -t tree /dev/null
+        empty_tree=4b825dc6
+
+        id=$(echo $oldrev | cut -b-7)
+        id2=$(echo $newrev | cut -b-7)
+        if [ $oldrev = $empty ]; then id=$empty_tree; fi
+        if [ $newrev = $empty ]; then id2=$empty_tree; fi
+
+        case $receive_mode in
+          create)
+            #git log --oneline $id2
+            link="http://cd/cgit/$GIT_SSH_REPO/"
+            ;;
+          fast-forward|non-fast-forward)
+            #git diff --stat $id..$id2
+            link="http://cd/cgit/$GIT_SSH_REPO/diff/?h=$h&id=$id&id2=$id2"
+            ;;
+        esac
+
+        #host=$nick
+        #$host $GIT_SSH_REPO $ref $link
+        message="''${message+$message
+      }$GIT_SSH_USER $receive_mode pushed $link"
+      done
+
+      if test -n "''${message-}"; then
+        exec ${irc-announce-script} \
+          "$server" \
+          "$port" \
+          "$nick" \
+          "$channel" \
+          "$message"
+      fi
+    '';
+  };
+
 in
-commands // receive-modes // permissions // refs
+commands // receive-modes // permissions // refs // hooks