Support mercurial (hg) dependencies

2 files changed, 123 insertions, 1 deletions

diff --git a/src/rebar_fetch.erl b/src/rebar_fetch.erl
index 4dfd790..9c427df 100644
--- a/src/rebar_fetch.erl
+++ b/src/rebar_fetch.erl
@@ -17,7 +17,8 @@
 -include_lib("providers/include/providers.hrl").
 
 %% map short versions of resources to module names
--define(RESOURCES, [{git, rebar_git_resource}, {pkg, rebar_pkg_resource}]).
+-define(RESOURCES, [{git, rebar_git_resource}, {pkg, rebar_pkg_resource},
+                    {hg, rebar_hg_resource}]).
 
 -spec lock_source(file:filename_all(), rebar_resource:resource()) ->
                          rebar_resource:resource() | {error, string()}.
diff --git a/src/rebar_hg_resource.erl b/src/rebar_hg_resource.erl
new file mode 100644
index 0000000..a0ebb6d
--- /dev/null
+++ b/src/rebar_hg_resource.erl
@@ -0,0 +1,121 @@
+%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*-
+%% ex: ts=4 sw=4 et
+-module(rebar_hg_resource).
+
+-behaviour(rebar_resource).
+
+-export([lock/2
+        ,download/3
+        ,needs_update/2
+        ,make_vsn/1]).
+
+-include("rebar.hrl").
+
+lock(AppDir, {hg, Url, _}) ->
+    lock(AppDir, {hg, Url});
+lock(AppDir, {hg, Url}) ->
+    Ref = get_ref(AppDir),
+    {hg, Url, {ref, Ref}}.
+
+%% Return `true' if either the hg url or tag/branch/ref is not the same as
+%% the currently checked out repo for the dep
+needs_update(Dir, {hg, Url, {tag, Tag}}) ->
+    Ref = get_ref(Dir),
+    {ClosestTag, Distance} = get_tag_distance(Dir, Ref),
+    ?DEBUG("Comparing hg tag ~s with ref ~s (closest tag is ~s at distance ~s)",
+           [Tag, Ref, ClosestTag, Distance]),
+    not ((Distance =:= "0") andalso (Tag =:= ClosestTag)
+         andalso compare_url(Dir, Url));
+needs_update(Dir, {hg, Url, {branch, Branch}}) ->
+    Ref = get_ref(Dir),
+    BRef = get_branch_ref(Dir, Branch),
+    not ((Ref =:= BRef) andalso compare_url(Dir, Url));
+needs_update(Dir, {hg, Url, "default"}) ->
+    Ref = get_ref(Dir),
+    BRef = get_branch_ref(Dir, "default"),
+    not ((Ref =:= BRef) andalso compare_url(Dir, Url));
+needs_update(Dir, {hg, Url, Ref}) ->
+    LocalRef = get_ref(Dir),
+    TargetRef = case Ref of
+        {ref, Ref1} ->
+            Length = length(LocalRef),
+            if Length >= 7 -> lists:sublist(Ref1, Length);
+               Length < 7 -> Ref1
+            end;
+        Ref1 ->
+            Ref1
+    end,
+    ?DEBUG("Comparing hg ref ~s with ~s", [Ref1, LocalRef]),
+    not ((LocalRef =:= TargetRef) andalso compare_url(Dir, Url)).
+
+download(Dir, {hg, Url}, State) ->
+    ?WARN("WARNING: It is recommended to use {branch, Name}, {tag, Tag} or {ref, Ref}, otherwise updating the dep may not work as expected.", []),
+    download(Dir, {hg, Url, {branch, "default"}}, State);
+download(Dir, {hg, Url, ""}, State) ->
+    ?WARN("WARNING: It is recommended to use {branch, Name}, {tag, Tag} or {ref, Ref}, otherwise updating the dep may not work as expected.", []),
+    download(Dir, {hg, Url, {branch, "default"}}, State);
+download(Dir, {hg, Url, {branch, Branch}}, _State) ->
+    ok = filelib:ensure_dir(Dir),
+    rebar_utils:sh(?FMT("hg clone -q -b ~s ~s ~s",
+                       [Branch, Url, filename:basename(Dir)]),
+                   [{cd, filename:dirname(Dir)}]);
+download(Dir, {hg, Url, {tag, Tag}}, _State) ->
+    ok = filelib:ensure_dir(Dir),
+    rebar_utils:sh(?FMT("hg clone -q -r ~s ~s ~s",
+                        [Tag, Url, filename:basename(Dir)]),
+                   [{cd, filename:dirname(Dir)}]);
+download(Dir, {hg, Url, {ref, Ref}}, _State) ->
+    ok = filelib:ensure_dir(Dir),
+    rebar_utils:sh(?FMT("hg clone -q -r ~s ~s ~s",
+                        [Ref, Url, filename:basename(Dir)]),
+                   [{cd, filename:dirname(Dir)}]);
+download(Dir, {hg, Url, Rev}, _State) ->
+    ok = filelib:ensure_dir(Dir),
+    rebar_utils:sh(?FMT("hg clone -q -r ~s ~s ~s",
+                        [Rev, Url, filename:basename(Dir)]),
+                   [{cd, filename:dirname(Dir)}]).
+
+make_vsn(Dir) ->
+    BaseHg = "hg -R '" ++ Dir ++ "' ",
+    Ref = get_ref(Dir),
+    Cmd = BaseHg ++ "log --template \"{latesttag}+build.{latesttagdistance}.rev.{node|short}\""
+          " --rev " ++ Ref,
+    RawVsn = string:strip(os:cmd(Cmd), both, $\n),
+    Vsn = case RawVsn of
+        "null+" ++ Rest -> "0.0.0+" ++ Rest;
+        _ -> RawVsn
+    end,
+    {plain, Vsn}.
+
+%%% Internal functions
+
+compare_url(Dir, Url) ->
+    CurrentUrl = string:strip(os:cmd("hg -R '" ++ Dir ++"' paths default"), both, $\n),
+    CurrentUrl1 = string:strip(CurrentUrl, both, $\r),
+    parse_hg_url(CurrentUrl1) =:= parse_hg_url(Url).
+
+get_ref(Dir) ->
+    string:strip(os:cmd("hg -R '" ++ Dir ++ "' --debug id -i"), both, $\n).
+
+get_tag_distance(Dir, Ref) ->
+    Log = string:strip(os:cmd("hg -R '" ++ Dir ++ "' "
+                              "log --template \"{latesttag}-{latesttagdistance}\n\" "
+                              "--rev " ++ Ref),
+                       both, $\n),
+    [Tag, Distance] = re:split(Log, "-([0-9]+)$", [{parts,0}]),
+    {Tag, Distance}.
+
+get_branch_ref(Dir, Branch) ->
+    string:strip(
+        os:cmd("hg -R '" ++ Dir ++ "' log --template \"{node}\n\" --rev " ++ Branch),
+        both, $\n).
+
+parse_hg_url("ssh://" ++ HostPath) ->
+    [Host | Path] = string:tokens(HostPath, "/"),
+    {Host, filename:rootname(filename:join(Path), ".hg")};
+parse_hg_url("http://" ++ HostPath) ->
+    [Host | Path] = string:tokens(HostPath, "/"),
+    {Host, filename:rootname(filename:join(Path), ".hg")};
+parse_hg_url("https://" ++ HostPath) ->
+    [Host | Path] = string:tokens(HostPath, "/"),
+    {Host, filename:rootname(filename:join(Path), ".hg")}.