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      5 // modification, are permitted provided that the following conditions are
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      9 //   notice, this list of conditions and the following disclaimer.
     10 // * Redistributions in binary form must reproduce the above copyright
     11 //   notice, this list of conditions and the following disclaimer in the
     12 //   documentation and/or other materials provided with the distribution.
     13 // * Neither the name of Google Inc. nor the names of its contributors
     14 //   may be used to endorse or promote products derived from this software
     15 //   without specific prior written permission.
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     17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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     28 
     29 /// \file utils/process/child.hpp
     30 /// Spawning and manipulation of children processes.
     31 ///
     32 /// The child module provides a set of functions to spawn subprocesses with
     33 /// different settings, and the corresponding set of classes to interact with
     34 /// said subprocesses.  The interfaces to fork subprocesses are very simplified
     35 /// and only provide the minimum functionality required by the rest of the
     36 /// project.
     37 ///
     38 /// Be aware that the semantics of the fork and wait methods exposed by this
     39 /// module are slightly different from that of the native calls.  Any process
     40 /// spawned by fork here will be isolated in its own process group; once any of
     41 /// such children processes is awaited for, its whole process group will be
     42 /// terminated.  This is the semantics we want in the above layers to ensure
     43 /// that test programs (and, for that matter, external utilities) do not leak
     44 /// subprocesses on the system.
     45 
     46 #if !defined(UTILS_PROCESS_CHILD_HPP)
     47 #define UTILS_PROCESS_CHILD_HPP
     48 
     49 #include <istream>
     50 #include <memory>
     51 #include <string>
     52 #include <vector>
     53 
     54 #include "utils/fs/path.hpp"
     55 #include "utils/noncopyable.hpp"
     56 #include "utils/process/status.hpp"
     57 
     58 namespace utils {
     59 namespace process {
     60 
     61 
     62 /// Arguments to a program, without the program name.
     63 typedef std::vector< std::string > args_vector;
     64 
     65 
     66 /// Child process spawner and controller.
     67 class child : noncopyable {
     68     struct impl;
     69 
     70     /// Pointer to the shared internal implementation.
     71     std::unique_ptr< impl > _pimpl;
     72 
     73     static std::unique_ptr< child > fork_capture_aux(void);
     74 
     75     static std::unique_ptr< child > fork_files_aux(const fs::path&,
     76                                                  const fs::path&);
     77 
     78     explicit child(impl *);
     79 
     80 public:
     81     ~child(void);
     82 
     83     template< typename Hook >
     84     static std::unique_ptr< child > fork_capture(Hook);
     85     std::istream& output(void);
     86 
     87     template< typename Hook >
     88     static std::unique_ptr< child > fork_files(Hook, const fs::path&,
     89                                              const fs::path&);
     90 
     91     static std::unique_ptr< child > spawn_capture(
     92         const fs::path&, const args_vector&);
     93     static std::unique_ptr< child > spawn_files(
     94         const fs::path&, const args_vector&, const fs::path&, const fs::path&);
     95 
     96     int pid(void) const;
     97 
     98     status wait(void);
     99 };
    100 
    101 
    102 }  // namespace process
    103 }  // namespace utils
    104 
    105 #endif  // !defined(UTILS_PROCESS_CHILD_HPP)
    106