Program.h revision f630e49efc7bf3f1716b6daab3c2cc11a908754a 
1//===- llvm/Support/Program.h ------------------------------------*- C++ -*-===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file declares the llvm::sys::Program class.
11//
12//===----------------------------------------------------------------------===//
13
14#ifndef LLVM_SYSTEM_PROGRAM_H
15#define LLVM_SYSTEM_PROGRAM_H
16
17#include "llvm/Support/Path.h"
18
19namespace llvm {
20class error_code;
21namespace sys {
22
23  // TODO: Add operations to communicate with the process, redirect its I/O,
24  // etc.
25
26  /// This class provides an abstraction for programs that are executable by the
27  /// operating system. It provides a platform generic way to find executable
28  /// programs from the path and to execute them in various ways. The sys::Path
29  /// class is used to specify the location of the Program.
30  /// @since 1.4
31  /// @brief An abstraction for finding and executing programs.
32  class Program {
33    /// Opaque handle for target specific data.
34    void *Data_;
35
36    // Noncopyable.
37    Program(const Program& other) LLVM_DELETED_FUNCTION;
38    Program& operator=(const Program& other) LLVM_DELETED_FUNCTION;
39
40    /// @name Methods
41    /// @{
42  public:
43
44    Program();
45    ~Program();
46
47    /// Return process ID of this program.
48    unsigned GetPid() const;
49
50    /// This function executes the program using the \p arguments provided.  The
51    /// invoked program will inherit the stdin, stdout, and stderr file
52    /// descriptors, the environment and other configuration settings of the
53    /// invoking program. If Path::executable() does not return true when this
54    /// function is called then a std::string is thrown.
55    /// @returns false in case of error, true otherwise.
56    /// @see FindProgramByName
57    /// @brief Executes the program with the given set of \p args.
58    bool Execute
59    ( const Path& path,  ///< sys::Path object providing the path of the
60      ///< program to be executed. It is presumed this is the result of
61      ///< the FindProgramByName method.
62      const char** args, ///< A vector of strings that are passed to the
63      ///< program.  The first element should be the name of the program.
64      ///< The list *must* be terminated by a null char* entry.
65      const char ** env = 0, ///< An optional vector of strings to use for
66      ///< the program's environment. If not provided, the current program's
67      ///< environment will be used.
68      const sys::Path** redirects = 0, ///< An optional array of pointers to
69      ///< Paths. If the array is null, no redirection is done. The array
70      ///< should have a size of at least three. If the pointer in the array
71      ///< are not null, then the inferior process's stdin(0), stdout(1),
72      ///< and stderr(2) will be redirected to the corresponding Paths.
73      ///< When an empty Path is passed in, the corresponding file
74      ///< descriptor will be disconnected (ie, /dev/null'd) in a portable
75      ///< way.
76      unsigned memoryLimit = 0, ///< If non-zero, this specifies max. amount
77      ///< of memory can be allocated by process. If memory usage will be
78      ///< higher limit, the child is killed and this call returns. If zero
79      ///< - no memory limit.
80      std::string* ErrMsg = 0 ///< If non-zero, provides a pointer to a string
81      ///< instance in which error messages will be returned. If the string
82      ///< is non-empty upon return an error occurred while invoking the
83      ///< program.
84      );
85
86    /// This function waits for the program to exit. This function will block
87    /// the current program until the invoked program exits.
88    /// @returns an integer result code indicating the status of the program.
89    /// A zero or positive value indicates the result code of the program.
90    /// -1 indicates failure to execute
91    /// -2 indicates a crash during execution or timeout
92    /// @see Execute
93    /// @brief Waits for the program to exit.
94    int Wait
95    ( const Path& path, ///< The path to the child process executable.
96      unsigned secondsToWait, ///< If non-zero, this specifies the amount
97      ///< of time to wait for the child process to exit. If the time
98      ///< expires, the child is killed and this call returns. If zero,
99      ///< this function will wait until the child finishes or forever if
100      ///< it doesn't.
101      std::string* ErrMsg ///< If non-zero, provides a pointer to a string
102      ///< instance in which error messages will be returned. If the string
103      ///< is non-empty upon return an error occurred while waiting.
104      );
105
106    /// This function terminates the program.
107    /// @returns true if an error occurred.
108    /// @see Execute
109    /// @brief Terminates the program.
110    bool Kill
111    ( std::string* ErrMsg = 0 ///< If non-zero, provides a pointer to a string
112      ///< instance in which error messages will be returned. If the string
113      ///< is non-empty upon return an error occurred while killing the
114      ///< program.
115      );
116
117    /// This static constructor (factory) will attempt to locate a program in
118    /// the operating system's file system using some pre-determined set of
119    /// locations to search (e.g. the PATH on Unix). Paths with slashes are
120    /// returned unmodified.
121    /// @returns A Path object initialized to the path of the program or a
122    /// Path object that is empty (invalid) if the program could not be found.
123    /// @brief Construct a Program by finding it by name.
124    static Path FindProgramByName(const std::string& name);
125
126    // These methods change the specified standard stream (stdin, stdout, or
127    // stderr) to binary mode. They return errc::success if the specified stream
128    // was changed. Otherwise a platform dependent error is returned.
129    static error_code ChangeStdinToBinary();
130    static error_code ChangeStdoutToBinary();
131    static error_code ChangeStderrToBinary();
132
133    /// A convenience function equivalent to Program prg; prg.Execute(..);
134    /// prg.Wait(..);
135    /// @see Execute, Wait
136    static int ExecuteAndWait(const Path& path,
137                              const char** args,
138                              const char ** env = 0,
139                              const sys::Path** redirects = 0,
140                              unsigned secondsToWait = 0,
141                              unsigned memoryLimit = 0,
142                              std::string* ErrMsg = 0);
143
144    /// A convenience function equivalent to Program prg; prg.Execute(..);
145    /// @see Execute
146    static void ExecuteNoWait(const Path& path,
147                              const char** args,
148                              const char ** env = 0,
149                              const sys::Path** redirects = 0,
150                              unsigned memoryLimit = 0,
151                              std::string* ErrMsg = 0);
152
153    /// @}
154
155  };
156}
157}
158
159#endif
160