Add infrastructure for policies that disallow commands

Add cmCommand::Disallowed helper to check the setting of a policy that
disallows the command.  Add a RunCMake.DisallowedCommands test
placeholder.  Add a Help/policy/DISALLOWED_COMMAND.txt file for
inclusion by each policy document to avoid duplication of the common
text.

1 files changed, 19 insertions, 0 deletions

diff --git a/Source/cmCommand.h b/Source/cmCommand.h
index 83184a0e4a..e1488571f6 100644
--- a/Source/cmCommand.h
+++ b/Source/cmCommand.h
@@ -173,6 +173,25 @@ public:
     this->Error += e;
     }
 
+  /** Check if the command is disallowed by a policy.  */
+  bool Disallowed(cmPolicies::PolicyID pol, const char* e)
+    {
+    switch(this->Makefile->GetPolicyStatus(pol))
+      {
+      case cmPolicies::WARN:
+        this->Makefile->IssueMessage(cmake::AUTHOR_WARNING,
+          this->Makefile->GetPolicies()->GetPolicyWarning(pol));
+      case cmPolicies::OLD:
+        return false;
+      case cmPolicies::REQUIRED_IF_USED:
+      case cmPolicies::REQUIRED_ALWAYS:
+      case cmPolicies::NEW:
+        this->Makefile->IssueMessage(cmake::FATAL_ERROR, e);
+        break;
+      }
+    return true;
+    }
+
 protected:
   cmMakefile* Makefile;
   cmCommandArgumentsHelper Helper;