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24 // SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25
26 #include <iostream>
27 #include <string>
28
29 #include "google/protobuf/compiler/plugin.upb.h"
30 #include "upbc/subprocess.h"
31 #include "upbc/upbdev.h"
32
33 static constexpr char kDefaultPlugin[] = "protoc_dart_plugin";
34
main()35 int main() {
36 upb_Arena* a = upb_Arena_New();
37 upb_Status status;
38 upb_Status_Clear(&status);
39
40 // Read (binary) stdin into a string.
41 const std::string input = {std::istreambuf_iterator<char>(std::cin),
42 std::istreambuf_iterator<char>()};
43
44 // Parse the request.
45 auto inner_request = google_protobuf_compiler_CodeGeneratorRequest_parse(
46 input.c_str(), input.size(), a);
47
48 // Check the request for a plugin name.
49 std::string plugin = kDefaultPlugin;
50 if (google_protobuf_compiler_CodeGeneratorRequest_has_parameter(inner_request)) {
51 auto param = google_protobuf_compiler_CodeGeneratorRequest_parameter(inner_request);
52 plugin = std::string(param.data, param.size);
53 }
54
55 // Wrap the request inside a upbc_CodeGeneratorRequest and JSON-encode it.
56 const upb_StringView sv =
57 upbdev_ProcessInput(input.data(), input.size(), a, &status);
58 if (!upb_Status_IsOk(&status)) {
59 std::cerr << status.msg << std::endl;
60 return -1;
61 }
62
63 // Launch the subprocess.
64 upbc::Subprocess subprocess;
65 subprocess.Start(plugin, upbc::Subprocess::SEARCH_PATH);
66
67 // Exchange JSON strings with the subprocess.
68 const std::string json_request = std::string(sv.data, sv.size);
69 std::string json_response, error;
70 const bool ok = subprocess.Communicate(json_request, &json_response, &error);
71 if (!ok) {
72 // Dump the JSON request to stderr if we can't launch the next plugin.
73 std::cerr << json_request << std::endl;
74 return -1;
75 }
76
77 // Decode, serialize, and write the JSON response.
78 upbdev_ProcessOutput(json_response.data(), json_response.size(), a, &status);
79 if (!upb_Status_IsOk(&status)) {
80 std::cerr << status.msg << std::endl;
81 return -1;
82 }
83
84 upb_Arena_Free(a);
85 return 0;
86 }
87