1 files changed, 85 insertions, 0 deletions
diff --git a/src/source-error-handler.cc b/src/source-error-handler.cc
new file mode 100644
index 00000000..32976b77
--- /dev/null
+++ b/src/source-error-handler.cc
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2017 WebAssembly Community Group participants
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "source-error-handler.h"
+
+#include <algorithm>
+
+namespace wabt {
+
+std::string SourceErrorHandler::DefaultErrorMessage(
+    const Location* loc,
+    const std::string& error,
+    const std::string& source_line,
+    size_t source_line_column_offset) {
+  std::string result = string_printf("%s:%d:%d: %s\n", loc->filename, loc->line,
+                                     loc->first_column, error.c_str());
+  if (!source_line.empty()) {
+    result += source_line;
+    result += '\n';
+
+    size_t num_spaces = (loc->first_column - 1) - source_line_column_offset;
+    size_t num_carets = loc->last_column - loc->first_column;
+    num_carets = std::min(num_carets, source_line.size() - num_spaces);
+    num_carets = std::max<size_t>(num_carets, 1);
+    result.append(num_spaces, ' ');
+    result.append(num_carets, '^');
+    result += '\n';
+  }
+  return result;
+}
+
+SourceErrorHandlerFile::SourceErrorHandlerFile(FILE* file,
+                                               const std::string& header,
+                                               PrintHeader print_header,
+                                               size_t source_line_max_length)
+    : file_(file),
+      header_(header),
+      print_header_(print_header),
+      source_line_max_length_(source_line_max_length) {}
+
+bool SourceErrorHandlerFile::OnError(const Location* loc,
+                                     const std::string& error,
+                                     const std::string& source_line,
+                                     size_t source_line_column_offset) {
+  PrintErrorHeader();
+  std::string message =
+      DefaultErrorMessage(loc, error, source_line, source_line_column_offset);
+  fwrite(message.data(), 1, message.size(), file_);
+  return true;
+}
+
+void SourceErrorHandlerFile::PrintErrorHeader() {
+  if (header_.empty())
+    return;
+
+  switch (print_header_) {
+    case PrintHeader::Never:
+      break;
+
+    case PrintHeader::Once:
+      print_header_ = PrintHeader::Never;
+    // Fallthrough.
+
+    case PrintHeader::Always:
+      fprintf(file_, "%s:\n", header_.c_str());
+      break;
+  }
+  // If there's a header, indent the following message.
+  fprintf(file_, "  ");
+}
+
+}  // namespace wabt