feat: add plantransformer tool to convert any plan to any format (#98)

src/substrait/common/CMakeLists.txt

@@ -27,3 +27,7 @@ endif()
 install(TARGETS substrait_io LIBRARY DESTINATION ${CMAKE_INSTALL_LIBDIR})
 install(FILES ../../../include/substrait/common/Io.h
         DESTINATION "${CMAKE_INSTALL_INCLUDEDIR}/substrait/common")
+
+add_executable(plantransformer PlanTransformerTool.cpp)
+
+target_link_libraries(plantransformer substrait_io)

src/substrait/common/PlanTransformerTool.cpp

@@ -0,0 +1,54 @@
+/* SPDX-License-Identifier: Apache-2.0 */
+
+#include <iostream>
+
+#include "substrait/common/Io.h"
+
+namespace io::substrait {
+namespace {
+
+PlanFileFormat planFileFormatFromText(std::string_view str) {
+  std::string foo;
+  foo.resize(str.size());
+  std::transform(str.begin(), str.end(), foo.begin(), [](unsigned char c) {
+    return std::tolower(c);
+  });
+  if (foo == "binary") {
+    return PlanFileFormat::kBinary;
+  } else if (foo == "json") {
+    return PlanFileFormat::kJson;
+  } else if (foo == "prototext") {
+    return PlanFileFormat::kProtoText;
+  } else if (foo == "text") {
+    return PlanFileFormat::kText;
+  }
+  // If the format can't be understood, default to text.
+  return PlanFileFormat::kText;
+}
+
+} // namespace
+} // namespace io::substrait
+
+int main(int argc, char* argv[]) {
+  if (argc <= 3) {
+    printf(
+        "Usage:  plantransformer <inputfilename> <outputfilename> [BINARY|JSON|PROTOTEXT|TEXT]\n");
+    return EXIT_FAILURE;
+  }
+
+  auto planOrError = io::substrait::loadPlan(argv[1]);
+  if (!planOrError.ok()) {
+    std::cerr << planOrError.status() << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  auto format = io::substrait::planFileFormatFromText(argv[3]);
+
+  auto result = io::substrait::savePlan(*planOrError, argv[2], format);
+  if (!result.ok()) {
+    std::cerr << result << std::endl;
+    return EXIT_FAILURE;
+  }
+
+  return EXIT_SUCCESS;
+}