file: Add READ_SYMLINK sub-command

2 files changed, 31 insertions, 0 deletions

diff --git a/Source/cmFileCommand.cxx b/Source/cmFileCommand.cxx
index 73ff5a1..7fc717d 100644
--- a/Source/cmFileCommand.cxx
+++ b/Source/cmFileCommand.cxx
@@ -180,6 +180,9 @@ bool cmFileCommand::InitialPass(std::vector<std::string> const& args,
   if (subCommand == "SIZE") {
     return this->HandleSizeCommand(args);
   }
+  if (subCommand == "READ_SYMLINK") {
+    return this->HandleReadSymlinkCommand(args);
+  }
 
   std::string e = "does not recognize sub-command " + subCommand;
   this->SetError(e);
@@ -3638,3 +3641,30 @@ bool cmFileCommand::HandleSizeCommand(std::vector<std::string> const& args)
 
   return true;
 }
+
+bool cmFileCommand::HandleReadSymlinkCommand(
+  std::vector<std::string> const& args)
+{
+  if (args.size() != 3) {
+    std::ostringstream e;
+    e << args[0] << " requires a file name and output variable";
+    this->SetError(e.str());
+    return false;
+  }
+
+  const std::string& filename = args[1];
+  const std::string& outputVariable = args[2];
+
+  std::string result;
+  if (!cmSystemTools::ReadSymlink(filename, result)) {
+    std::ostringstream e;
+    e << "READ_SYMLINK requested of path that is not a symlink:\n  "
+      << filename;
+    this->SetError(e.str());
+    return false;
+  }
+
+  this->Makefile->AddDefinition(outputVariable, result.c_str());
+
+  return true;
+}
diff --git a/Source/cmFileCommand.h b/Source/cmFileCommand.h
index 01e007d..fe05c98 100644
--- a/Source/cmFileCommand.h
+++ b/Source/cmFileCommand.h
@@ -60,6 +60,7 @@ protected:
   bool HandleGenerateCommand(std::vector<std::string> const& args);
   bool HandleLockCommand(std::vector<std::string> const& args);
   bool HandleSizeCommand(std::vector<std::string> const& args);
+  bool HandleReadSymlinkCommand(std::vector<std::string> const& args);
 
 private:
   void AddEvaluationFile(const std::string& inputName,