1 files changed, 75 insertions, 0 deletions
diff --git a/gcc/rust/parse/rust-cfg-parser.cc b/gcc/rust/parse/rust-cfg-parser.cc
new file mode 100644
index 0000000..a6f34b6
--- /dev/null
+++ b/gcc/rust/parse/rust-cfg-parser.cc
@@ -0,0 +1,75 @@
+#include "rust-cfg-parser.h"
+#include "selftest.h"
+
+namespace Rust {
+bool
+parse_cfg_option (const std::string &input, std::string &key,
+		  std::string &value)
+{
+  key.clear ();
+  value.clear ();
+
+  auto equal = input.find ('=');
+
+  // If there is no equal sign, it means there is no value. Clean up the key
+  // and return
+  if (equal == std::string::npos)
+    {
+      key = input;
+
+      // FIXME: Make sure key is a proper identifier
+
+      return true;
+    }
+
+  key = input.substr (0, equal);
+
+  auto remaining_input = input.substr (equal + 1);
+  if (remaining_input[0] != '"' || remaining_input.back () != '"')
+    return false;
+
+  // Remove the quotes around the value, by advancing one character
+  value = remaining_input.substr (1);
+  // And trimming the rightmost character. This is fine since we've already
+  // checked that both the first and last characters were quotes.
+  value.resize (value.size () - 1);
+
+  // FIXME: We need to sanitize here and make sure that both key and value
+  // are proper identifiers
+
+  return true;
+}
+
+} // namespace Rust
+
+#if CHECKING_P
+
+namespace selftest {
+
+void
+rust_cfg_parser_test (void)
+{
+  std::string key;
+  std::string value;
+
+  ASSERT_TRUE (Rust::parse_cfg_option ("key-no-value", key, value));
+  ASSERT_EQ (key, "key-no-value");
+  ASSERT_TRUE (value.empty ());
+
+  ASSERT_TRUE (Rust::parse_cfg_option ("k=\"v\"", key, value));
+  ASSERT_EQ (key, "k");
+  ASSERT_EQ (value, "v");
+
+  // values should be between double quotes
+  ASSERT_FALSE (Rust::parse_cfg_option ("k=v", key, value));
+
+  // No value is an error if there is an equal sign
+  ASSERT_FALSE (Rust::parse_cfg_option ("k=", key, value));
+
+  // No key is an error
+  ASSERT_FALSE (Rust::parse_cfg_option ("=", key, value));
+  ASSERT_FALSE (Rust::parse_cfg_option ("=value", key, value));
+}
+} // namespace selftest
+
+#endif // CHECKING_P