lix/src/libutil/util.hh
Eelco Dolstra 4a373a3e9a * Implemented Eelco V.'s `nix-env -I' command to specify the default
path of the Nix expression to be used with the import, upgrade, and
  query commands.  For instance,

  $ nix-env -I ~/nixpkgs/pkgs/system/i686-linux.nix

  $ nix-env --query --available   [aka -qa]
  sylpheed-0.9.7
  bison-1.875
  pango-1.2.5
  subversion-0.35.1
  ...

  $ nix-env -i sylpheed

  $ nix-env -u subversion

  There can be only one default at a time.

* If the path to a Nix expression is a symlink, follow the symlink
  prior to resolving relative path references in the expression.
2004-01-05 16:26:43 +00:00

183 lines
3.7 KiB
C++

#ifndef __UTIL_H
#define __UTIL_H
#include <string>
#include <list>
#include <set>
#include <sstream>
#include <sys/types.h>
#include <dirent.h>
#include <unistd.h>
#include <boost/format.hpp>
using namespace std;
using namespace boost;
class Error : public exception
{
protected:
string err;
public:
Error(const format & f);
~Error() throw () { };
const char * what() const throw () { return err.c_str(); }
const string & msg() const throw () { return err; }
};
class SysError : public Error
{
public:
SysError(const format & f);
};
class UsageError : public Error
{
public:
UsageError(const format & f) : Error(f) { };
};
typedef list<string> Strings;
typedef set<string> StringSet;
/* Paths are just strings. */
typedef string Path;
typedef list<Path> Paths;
typedef set<Path> PathSet;
/* The canonical system name, as returned by config.guess. */
extern string thisSystem;
/* Return an absolutized path, resolving paths relative to the
specified directory, or the current directory otherwise. The path
is also canonicalised. */
Path absPath(Path path, Path dir = "");
/* Canonicalise a path (as in realpath(3)). */
Path canonPath(const Path & path);
/* Return the directory part of the given path, i.e., everything
before the final `/'. */
Path dirOf(const Path & path);
/* Return the base name of the given path, i.e., everything following
the final `/'. */
string baseNameOf(const Path & path);
/* Return true iff the given path exists. */
bool pathExists(const Path & path);
/* Read the contents (target) of a symbolic link. The result is not
in any way canonicalised. */
Path readLink(const Path & path);
/* Read the contents of a directory. The entries `.' and `..' are
removed. */
Strings readDirectory(const Path & path);
/* Delete a path; i.e., in the case of a directory, it is deleted
recursively. Don't use this at home, kids. */
void deletePath(const Path & path);
/* Make a path read-only recursively. */
void makePathReadOnly(const Path & path);
/* Create a temporary directory. */
Path createTempDir();
/* Create a file and write the given text to it. The file is written
in binary mode (i.e., no end-of-line conversions). The path should
not already exist. */
void writeStringToFile(const Path & path, const string & s);
/* Messages. */
typedef enum {
lvlError,
lvlInfo,
lvlTalkative,
lvlChatty,
lvlDebug,
lvlVomit
} Verbosity;
extern Verbosity verbosity; /* supress msgs > this */
class Nest
{
private:
bool nest;
public:
Nest();
~Nest();
void open(Verbosity level, const format & f);
};
void printMsg_(Verbosity level, const format & f);
#define startNest(varName, level, f) \
Nest varName; \
if (level <= verbosity) { \
varName.open(level, (f)); \
}
#define printMsg(level, f) \
do { \
if (level <= verbosity) { \
printMsg_(level, (f)); \
} \
} while (0)
#define debug(f) printMsg(lvlDebug, f)
/* Wrappers arount read()/write() that read/write exactly the
requested number of bytes. */
void readFull(int fd, unsigned char * buf, size_t count);
void writeFull(int fd, const unsigned char * buf, size_t count);
/* Automatic cleanup of resources. */
class AutoDelete
{
string path;
bool del;
public:
AutoDelete(const string & p);
~AutoDelete();
void cancel();
};
class AutoCloseFD
{
int fd;
public:
AutoCloseFD();
AutoCloseFD(int fd);
~AutoCloseFD();
void operator =(int fd);
operator int();
};
class AutoCloseDir
{
DIR * dir;
public:
AutoCloseDir();
AutoCloseDir(DIR * dir);
~AutoCloseDir();
void operator =(DIR * dir);
operator DIR *();
};
#endif /* !__UTIL_H */