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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 session; 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 "utils/process/child_fwd.hpp"
50
51#include <istream>
52#include <memory>
53#include <stdexcept>
54
55#include "utils/defs.hpp"
56#include "utils/fs/path_fwd.hpp"
57#include "utils/noncopyable.hpp"
58#include "utils/process/operations_fwd.hpp"
59#include "utils/process/status_fwd.hpp"
60
61namespace utils {
62namespace process {
63
64
65namespace detail {
66
67void report_error_and_abort(void) UTILS_NORETURN;
68void report_error_and_abort(const std::runtime_error&) UTILS_NORETURN;
69
70
71}  // namespace detail
72
73
74/// Child process spawner and controller.
75class child : noncopyable {
76    struct impl;
77
78    /// Pointer to the shared internal implementation.
79    std::auto_ptr< impl > _pimpl;
80
81    static std::auto_ptr< child > fork_capture_aux(void);
82
83    static std::auto_ptr< child > fork_files_aux(const fs::path&,
84                                                 const fs::path&);
85
86    explicit child(impl *);
87
88public:
89    ~child(void);
90
91    template< typename Hook >
92    static std::auto_ptr< child > fork_capture(Hook);
93    std::istream& output(void);
94
95    template< typename Hook >
96    static std::auto_ptr< child > fork_files(Hook, const fs::path&,
97                                             const fs::path&);
98
99    static std::auto_ptr< child > spawn_capture(
100        const fs::path&, const args_vector&);
101    static std::auto_ptr< child > spawn_files(
102        const fs::path&, const args_vector&, const fs::path&, const fs::path&);
103
104    int pid(void) const;
105
106    status wait(void);
107};
108
109
110}  // namespace process
111}  // namespace utils
112
113#endif  // !defined(UTILS_PROCESS_CHILD_HPP)
114