Windows: use junctions to link to installation directory.

Win32 have no good API for that (basically we need to resort to ioctl
call). Shelling out to mklink.

Needed for #276.

--
MOS_MIGRATED_REVID=115040968

1 files changed, 4 insertions, 2 deletions

diff --git a/src/main/cpp/blaze.cc b/src/main/cpp/blaze.cc
index 0c4fa76a79..336dbc2d8e 100644
--- a/src/main/cpp/blaze.cc
+++ b/src/main/cpp/blaze.cc
@@ -1009,6 +1009,8 @@ static void EnsureCorrectRunningVersion() {
   // installation is running.
   string installation_path = globals->options.output_base + "/install";
   char prev_installation[PATH_MAX + 1] = "";  // NULs the whole array
+  // TODO(dslomov): On Windows, readlink always fails,
+  // so we do the linking every time.
   if (readlink(installation_path.c_str(),
                prev_installation, PATH_MAX) == -1 ||
       prev_installation != globals->options.install_base) {
@@ -1016,8 +1018,8 @@ static void EnsureCorrectRunningVersion() {
       globals->restart_reason = NEW_VERSION;
     }
     unlink(installation_path.c_str());
-    if (symlink(globals->options.install_base.c_str(),
-                installation_path.c_str())) {
+    if (!SymlinkDirectories(globals->options.install_base.c_str(),
+                            installation_path.c_str())) {
       pdie(blaze_exit_code::LOCAL_ENVIRONMENTAL_ERROR,
            "failed to create installation symlink '%s'",
            installation_path.c_str());