cmFileCommand: Add CREATE_LINK subcommand

This brings the functionality of `cmake -E create_symlink` and more to scripts.

The default behavior is to create hard links.
The `SYMBOLIC` argument can be used to create symlinks instead.

The `COPY_ON_ERROR` argument enables a fallback to copying the file in case the link fails.

The `RESULT <var>` retrieves the error message generated by the system.
It is set to "0" on success.

Fixes: #16926

1 files changed, 16 insertions, 0 deletions

diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index be65853..a1c8c03 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -3134,3 +3134,19 @@ bool cmSystemTools::CreateSymlink(const std::string& origName,
 
   return true;
 }
+
+bool cmSystemTools::CreateLink(const std::string& origName,
+                               const std::string& newName)
+{
+  uv_fs_t req;
+  int err =
+    uv_fs_link(nullptr, &req, origName.c_str(), newName.c_str(), nullptr);
+  if (err) {
+    std::string e =
+      "failed to create link '" + newName + "': " + uv_strerror(err);
+    cmSystemTools::Error(e.c_str());
+    return false;
+  }
+
+  return true;
+}