5 #include <sigc++/sigc++.h>
6 #include <msp/core/mspcore_api.h>
7 #include <msp/core/mutex.h>
8 #include <msp/core/noncopyable.h>
17 Common interface for all I/O objects.
19 class MSPCORE_API Base: private NonCopyable
22 /** RAII synchronization primitive. Prevents concurrent access to the
23 target object during the lifetime of the Synchronize object. */
34 /** Emitted when there is no more data to be read. */
35 sigc::signal<void> signal_end_of_file;
37 /** Emitted when there is a nonlinearity in I/O (such as a file being
38 seeked) and any data buffered by upper layers needs to be flushed. */
39 sigc::signal<void> signal_flush_required;
41 /** Emitted when the object is deleted. Mainly for use by
43 sigc::signal<void> signal_deleted;
47 bool eof_flag = false;
48 Mutex *mutex = nullptr;
54 /** Sets blocking mode. When blocking is enabled, most operations won't
55 return until they can make progress. When blocking is disabled, these
56 operations may return immediately with a return code indicating that nothing
59 Blocking is enabled by default. */
60 virtual void set_block(bool) = 0;
62 /** Sets inheritance mode. When inheritance is enabled, the file descriptor
63 will persist through Process::execute.
65 Inheritance is disabled by default. */
66 virtual void set_inherit(bool) = 0;
68 /** Returns the current mode flags. */
69 Mode get_mode() const { return mode; }
72 void check_access(Mode) const;
74 virtual std::size_t do_write(const char *, std::size_t) = 0;
75 virtual std::size_t do_read(char *, std::size_t) = 0;
78 /** Writes data from a buffer. Subject to blocking. Returns the number of
79 bytes written, which may be zero for a non-blockin operation. */
80 std::size_t write(const char *b, std::size_t c) { return do_write(b, c); }
82 /** Writes a string. This is identical to calling
83 write(s.data(), s.size()). */
84 std::size_t write(const std::string &s) { return do_write(s.data(), s.size()); }
86 /** Writes a single character. This is identical to calling
88 virtual std::size_t put(char c) { return do_write(&c, 1); }
90 /** Reads data into a buffer. Subject to blocking. Returns the number of
91 bytes read, which may be zero for a non-blocking operation. */
92 std::size_t read(char *b, std::size_t c) { return do_read(b, c); }
94 /** Reads characters up to the next linefeed or end-of-file. The linefeed
95 is not included in the line. Returns true if a line was successfully read,
97 virtual bool getline(std::string &);
99 /** Reads a single character. Returns -1 if no character was available due
100 to end-of-file or non-blocking operation. */
107 /** Returns the end-of-file flag. Note that some types of objects won't
108 indicate end-of-file until you try to read at least one byte past the actual
109 end, while others indicate it when you've read the last byte. */
110 bool eof() const { return eof_flag; }
112 /** Returns the system-level handle for the object. Used by Console to
113 perform redirections. */
114 virtual const Handle &get_handle(Mode) = 0;