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Diffstat (limited to '0.8.0/paludis/util/pstream.hh')
| -rw-r--r-- | 0.8.0/paludis/util/pstream.hh | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/0.8.0/paludis/util/pstream.hh b/0.8.0/paludis/util/pstream.hh new file mode 100644 index 000000000..035eb189d --- /dev/null +++ b/0.8.0/paludis/util/pstream.hh @@ -0,0 +1,228 @@ +/* vim: set sw=4 sts=4 et foldmethod=syntax : */ + +/* + * Copyright (c) 2006 Ciaran McCreesh <ciaranm@ciaranm.org> + * + * This file is part of the Paludis package manager. Paludis is free software; + * you can redistribute it and/or modify it under the terms of the GNU General + * Public License version 2, as published by the Free Software Foundation. + * + * Paludis is distributed in the hope that it will be useful, but WITHOUT ANY + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS + * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more + * details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., 59 Temple + * Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#ifndef PALUDIS_GUARD_PALUDIS_PSTREAM_HH +#define PALUDIS_GUARD_PALUDIS_PSTREAM_HH 1 + +#include <cstdio> +#include <istream> +#include <limits> +#include <paludis/util/exception.hh> +#include <paludis/util/instantiation_policy.hh> +#include <paludis/util/pipe.hh> +#include <streambuf> +#include <string> + +/** \file + * Declarations for the PStream and PStreamInBuf classes, and related + * utilities. + * + * \ingroup grpsystem + */ + +namespace paludis +{ + /** + * Thrown if a PStream or PStreamInBuf encounters an error. + * + * \ingroup grpsystem + * \ingroup grpexceptions + */ + class PALUDIS_VISIBLE PStreamError : + public Exception + { + public: + ///\name Basic operations + ///\{ + + PStreamError(const std::string & message) throw (); + + ///\} + }; + + /** + * Input buffer class for a process, invoked using popen(3). + * + * Bidirectional I/O isn't supported since we haven't needed it yet, and + * because popen on Linux is unidirectional. + * + * See \ref TCppSL Ch. 13.13 for what we're doing here. The buffer code is + * based upon the "io/inbuf1.hpp" example in section 13.13.3. + * + * \ingroup grpsystem + */ + class PALUDIS_VISIBLE PStreamInBuf : + public std::streambuf, + private InstantiationPolicy<PStreamInBuf, instantiation_method::NonCopyableTag> + { + private: + Pipe stdout_pipe; + + const std::string _command; + + int _exit_status; + + pid_t child; + + protected: + /** + * Our file descriptor. + */ + int fd; + + /** + * At most how many characters can we put back? + */ + static const int putback_size = std::numeric_limits<unsigned>::digits >> 3; + + /** + * How large is our internal buffer? + */ + static const int buffer_size = 3 * putback_size; + + /** + * Internal buffer. + */ + char buffer[buffer_size]; + + /** + * Called when an underflow occurs. + */ + virtual int_type underflow(); + + public: + ///\name Basic operations + ///\{ + + /** + * Constructor. + * + * \param command The command to run. See PStream for discussion. + */ + PStreamInBuf(const std::string & command); + + ~PStreamInBuf(); + + ///\} + + /** + * What was our command? + */ + const std::string & command() const + { + return _command; + } + + /** + * What is our exit status? + */ + int exit_status(); + }; + + /** + * For internal use by PStream classes. + * + * \ingroup grpsystem + */ + namespace pstream_internals + { + /** + * Avoid base from member issues for PStream. + * + * \ingroup grpsystem + */ + struct PALUDIS_VISIBLE PStreamInBufBase : + private paludis::InstantiationPolicy<PStreamInBufBase, instantiation_method::NonCopyableTag> + { + /** + * Our buffer. + */ + PStreamInBuf buf; + + /** + * Constructor. + */ + PStreamInBufBase(const std::string & command) : + buf(command) + { + } + }; + } + + /** + * A PStream class is a standard input stream class whose contents comes + * from the output of an executed command. + * + * \ingroup grpsystem + */ + class PALUDIS_VISIBLE PStream : + private InstantiationPolicy<PStream, instantiation_method::NonCopyableTag>, + protected pstream_internals::PStreamInBufBase, + public std::istream + { + private: + static int _stderr_fd; + static int _stderr_close_fd; + + public: + ///\name Basic operations + ///\{ + + /** + * Constructor. + * + * \param command The command to execute. PATH is used, so there is + * usually no need to specify a full path. Arguments can be passed + * as part of the command. + */ + PStream(const std::string & command) : + PStreamInBufBase(command), + std::istream(&buf) + { + } + + ///\} + + /** + * What is our exit status? + */ + int exit_status() + { + return buf.exit_status(); + } + + /** + * Set a file descriptors to use for stderr and close on stderr + * (for all PStream instances). + */ + static void set_stderr_fd(const int, const int); + + /** + * File descriptor to use for stderr. + */ + static const int & stderr_fd; + + /** + * File descriptor to close for stderr. + */ + static const int & stderr_close_fd; + }; +} + +#endif |