From 36457566f9917dc7c0c348d012816a2ca333ef1b Mon Sep 17 00:00:00 2001 From: Ludovic Courtès Date: Wed, 17 Dec 2014 23:00:42 +0100 Subject: Merge branch 'nix' into 'master'. --- nix/libutil/util.hh | 349 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 349 insertions(+) create mode 100644 nix/libutil/util.hh (limited to 'nix/libutil/util.hh') diff --git a/nix/libutil/util.hh b/nix/libutil/util.hh new file mode 100644 index 0000000000..8bedfea9a0 --- /dev/null +++ b/nix/libutil/util.hh @@ -0,0 +1,349 @@ +#pragma once + +#include "types.hh" + +#include +#include +#include +#include +#include + +#include + + +namespace nix { + + +#define foreach(it_type, it, collection) \ + for (it_type it = (collection).begin(); it != (collection).end(); ++it) + +#define foreach_reverse(it_type, it, collection) \ + for (it_type it = (collection).rbegin(); it != (collection).rend(); ++it) + + +/* Return an environment variable. */ +string getEnv(const string & key, const string & def = ""); + +/* 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 by removing all `.' or `..' components and + double or trailing slashes. Optionally resolves all symlink + components such that each component of the resulting path is *not* + a symbolic link. */ +Path canonPath(const Path & path, bool resolveSymlinks = false); + +/* Return the directory part of the given canonical path, i.e., + everything before the final `/'. If the path is the root or an + immediate child thereof (e.g., `/foo'), this means an empty string + is returned. */ +Path dirOf(const Path & path); + +/* Return the base name of the given canonical path, i.e., everything + following the final `/'. */ +string baseNameOf(const Path & path); + +/* Check whether a given path is a descendant of the given + directory. */ +bool isInDir(const Path & path, const Path & dir); + +/* Get status of `path'. */ +struct stat lstat(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); + +bool isLink(const Path & path); + +/* Read the contents of a directory. The entries `.' and `..' are + removed. */ +Strings readDirectory(const Path & path); + +/* Read the contents of a file into a string. */ +string readFile(int fd); +string readFile(const Path & path, bool drain = false); + +/* Write a string to a file. */ +void writeFile(const Path & path, const string & s); + +/* Read a line from a file descriptor. */ +string readLine(int fd); + +/* Write a line to a file descriptor. */ +void writeLine(int fd, string s); + +/* Delete a path; i.e., in the case of a directory, it is deleted + recursively. Don't use this at home, kids. The second variant + returns the number of bytes and blocks freed. */ +void deletePath(const Path & path); + +void deletePath(const Path & path, unsigned long long & bytesFreed); + +/* Create a temporary directory. */ +Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix", + bool includePid = true, bool useGlobalCounter = true, mode_t mode = 0755); + +/* Create a directory and all its parents, if necessary. Returns the + list of created directories, in order of creation. */ +Paths createDirs(const Path & path); + +/* Create a symlink. */ +void createSymlink(const Path & target, const Path & link); + + +template +T singleton(const A & a) +{ + T t; + t.insert(a); + return t; +} + + +/* Messages. */ + + +typedef enum { + ltPretty, /* nice, nested output */ + ltEscapes, /* nesting indicated using escape codes (for log2xml) */ + ltFlat /* no nesting */ +} LogType; + +extern LogType logType; +extern Verbosity verbosity; /* suppress msgs > this */ + +class Nest +{ +private: + bool nest; +public: + Nest(); + ~Nest(); + void open(Verbosity level, const FormatOrString & fs); + void close(); +}; + +void printMsg_(Verbosity level, const FormatOrString & fs); + +#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) + +void warnOnce(bool & haveWarned, const FormatOrString & fs); + +void writeToStderr(const string & s); + +extern void (*_writeToStderr) (const unsigned char * buf, size_t count); + + +/* 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); + +MakeError(EndOfFile, Error) + + +/* Read a file descriptor until EOF occurs. */ +string drainFD(int fd); + + + +/* Automatic cleanup of resources. */ + + +template +struct AutoDeleteArray +{ + T * p; + AutoDeleteArray(T * p) : p(p) { } + ~AutoDeleteArray() + { + delete [] p; + } +}; + + +class AutoDelete +{ + Path path; + bool del; + bool recursive; +public: + AutoDelete(const Path & p, bool recursive = true); + ~AutoDelete(); + void cancel(); +}; + + +class AutoCloseFD +{ + int fd; +public: + AutoCloseFD(); + AutoCloseFD(int fd); + AutoCloseFD(const AutoCloseFD & fd); + ~AutoCloseFD(); + void operator =(int fd); + operator int() const; + void close(); + bool isOpen(); + int borrow(); +}; + + +class Pipe +{ +public: + AutoCloseFD readSide, writeSide; + void create(); +}; + + +class AutoCloseDir +{ + DIR * dir; +public: + AutoCloseDir(); + AutoCloseDir(DIR * dir); + ~AutoCloseDir(); + void operator =(DIR * dir); + operator DIR *(); + void close(); +}; + + +class Pid +{ + pid_t pid; + bool separatePG; + int killSignal; +public: + Pid(); + ~Pid(); + void operator =(pid_t pid); + operator pid_t(); + void kill(); + int wait(bool block); + void setSeparatePG(bool separatePG); + void setKillSignal(int signal); +}; + + +/* Kill all processes running under the specified uid by sending them + a SIGKILL. */ +void killUser(uid_t uid); + + +/* Run a program and return its stdout in a string (i.e., like the + shell backtick operator). */ +string runProgram(Path program, bool searchPath = false, + const Strings & args = Strings()); + +/* Close all file descriptors except stdin, stdout, stderr, and those + listed in the given set. Good practice in child processes. */ +void closeMostFDs(const set & exceptions); + +/* Set the close-on-exec flag for the given file descriptor. */ +void closeOnExec(int fd); + +/* Call vfork() if available, otherwise fork(). */ +extern pid_t (*maybeVfork)(); + + +/* User interruption. */ + +extern volatile sig_atomic_t _isInterrupted; + +void _interrupted(); + +void inline checkInterrupt() +{ + if (_isInterrupted) _interrupted(); +} + +MakeError(Interrupted, BaseError) + + +/* String tokenizer. */ +template C tokenizeString(const string & s, const string & separators = " \t\n\r"); + + +/* Concatenate the given strings with a separator between the + elements. */ +string concatStringsSep(const string & sep, const Strings & ss); +string concatStringsSep(const string & sep, const StringSet & ss); + + +/* Remove trailing whitespace from a string. */ +string chomp(const string & s); + + +/* Convert the exit status of a child as returned by wait() into an + error string. */ +string statusToString(int status); + +bool statusOk(int status); + + +/* Parse a string into an integer. */ +template bool string2Int(const string & s, N & n) +{ + std::istringstream str(s); + str >> n; + return str && str.get() == EOF; +} + +template string int2String(N n) +{ + std::ostringstream str; + str << n; + return str.str(); +} + + +/* Return true iff `s' ends in `suffix'. */ +bool hasSuffix(const string & s, const string & suffix); + + +/* Read string `s' from stream `str'. */ +void expect(std::istream & str, const string & s); + + +/* Read a C-style string from stream `str'. */ +string parseString(std::istream & str); + + +/* Utility function used to parse legacy ATerms. */ +bool endOfList(std::istream & str); + + +/* Escape a string that contains octal-encoded escape codes such as + used in /etc/fstab and /proc/mounts (e.g. "foo\040bar" decodes to + "foo bar"). */ +string decodeOctalEscaped(const string & s); + + +/* Exception handling in destructors: print an error message, then + ignore the exception. */ +void ignoreException(); + + +} -- cgit v1.2.3