rt: Factor out the logic that handles the various magic debug environment variables

1 files changed, 33 insertions, 0 deletions

diff --git a/src/rt/rust_debug.h b/src/rt/rust_debug.h
new file mode 100644
index 00000000000..f7c444324f7
--- /dev/null
+++ b/src/rt/rust_debug.h
@@ -0,0 +1,33 @@
+// Routines useful when debugging the Rust runtime.
+
+#ifndef RUST_DEBUG_H
+#define RUST_DEBUG_H
+
+#include <cstdlib>
+
+namespace debug {
+
+class flag {
+private:
+    const char *name;
+    bool valid;
+    bool value;
+
+public:
+    flag(const char *in_name) : name(in_name), valid(false) {}
+
+    bool operator*() {
+        // FIXME: We ought to lock this.
+        if (!valid) {
+            char *ev = getenv(name);
+            value = ev && ev[0] != '\0' && ev[0] != '0';
+            valid = true;
+        }
+        return value;
+    }
+};
+
+}   // end namespace debug
+
+#endif
+