subprocess.h revision d0332953cda33fb4f8e24ebff9c49159b69c43d6 
1// Protocol Buffers - Google's data interchange format
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30
31// Author: kenton@google.com (Kenton Varda)
32
33#ifndef GOOGLE_PROTOBUF_COMPILER_SUBPROCESS_H__
34#define GOOGLE_PROTOBUF_COMPILER_SUBPROCESS_H__
35
36#ifdef _WIN32
37#define WIN32_LEAN_AND_MEAN   // right...
38#include <windows.h>
39#else  // _WIN32
40#include <sys/types.h>
41#include <unistd.h>
42#endif  // !_WIN32
43
44#include <string>
45#include <google/protobuf/stubs/common.h>
46
47namespace google {
48namespace protobuf {
49
50class Message;
51
52namespace compiler {
53
54// Utility class for launching sub-processes.
55class Subprocess {
56 public:
57  Subprocess();
58  ~Subprocess();
59
60  enum SearchMode {
61    SEARCH_PATH,   // Use PATH environment variable.
62    EXACT_NAME     // Program is an exact file name; don't use the PATH.
63  };
64
65  // Start the subprocess.  Currently we don't provide a way to specify
66  // arguments as protoc plugins don't have any.
67  void Start(const string& program, SearchMode search_mode);
68
69  // Serialize the input message and pipe it to the subprocess's stdin, then
70  // close the pipe.  Meanwhile, read from the subprocess's stdout and parse
71  // the data into *output.  All this is done carefully to avoid deadlocks.
72  // Returns true if successful.  On any sort of error, returns false and sets
73  // *error to a description of the problem.
74  bool Communicate(const Message& input, Message* output, string* error);
75
76#ifdef _WIN32
77  // Given an error code, returns a human-readable error message.  This is
78  // defined here so that CommandLineInterface can share it.
79  static string Subprocess::Win32ErrorMessage(DWORD error_code);
80#endif
81
82 private:
83#ifdef _WIN32
84  DWORD process_start_error_;
85  HANDLE child_handle_;
86
87  // The file handles for our end of the child's pipes.  We close each and
88  // set it to NULL when no longer needed.
89  HANDLE child_stdin_;
90  HANDLE child_stdout_;
91
92#else  // _WIN32
93  pid_t child_pid_;
94
95  // The file descriptors for our end of the child's pipes.  We close each and
96  // set it to -1 when no longer needed.
97  int child_stdin_;
98  int child_stdout_;
99
100#endif  // !_WIN32
101};
102
103}  // namespace compiler
104}  // namespace protobuf
105
106}  // namespace google
107#endif  // GOOGLE_PROTOBUF_COMPILER_SUBPROCESS_H__
108