486 lines
12 KiB
C++
486 lines
12 KiB
C++
#pragma once
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#include "types.hh"
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#include "logging.hh"
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <dirent.h>
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#include <unistd.h>
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#include <signal.h>
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#include <functional>
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#include <limits>
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#include <cstdio>
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#include <map>
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#ifndef HAVE_STRUCT_DIRENT_D_TYPE
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#define DT_UNKNOWN 0
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#define DT_REG 1
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#define DT_LNK 2
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#define DT_DIR 3
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#endif
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namespace nix {
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/* Return an environment variable. */
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string getEnv(const string & key, const string & def = "");
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/* Get the entire environment. */
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std::map<std::string, std::string> getEnv();
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/* Return an absolutized path, resolving paths relative to the
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specified directory, or the current directory otherwise. The path
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is also canonicalised. */
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Path absPath(Path path, Path dir = "");
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/* Canonicalise a path by removing all `.' or `..' components and
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double or trailing slashes. Optionally resolves all symlink
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components such that each component of the resulting path is *not*
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a symbolic link. */
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Path canonPath(const Path & path, bool resolveSymlinks = false);
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/* Return the directory part of the given canonical path, i.e.,
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everything before the final `/'. If the path is the root or an
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immediate child thereof (e.g., `/foo'), this means an empty string
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is returned. */
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Path dirOf(const Path & path);
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/* Return the base name of the given canonical path, i.e., everything
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following the final `/'. */
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string baseNameOf(const Path & path);
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/* Check whether a given path is a descendant of the given
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directory. */
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bool isInDir(const Path & path, const Path & dir);
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/* Get status of `path'. */
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struct stat lstat(const Path & path);
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/* Return true iff the given path exists. */
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bool pathExists(const Path & path);
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/* Read the contents (target) of a symbolic link. The result is not
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in any way canonicalised. */
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Path readLink(const Path & path);
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bool isLink(const Path & path);
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/* Read the contents of a directory. The entries `.' and `..' are
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removed. */
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struct DirEntry
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{
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string name;
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ino_t ino;
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unsigned char type; // one of DT_*
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DirEntry(const string & name, ino_t ino, unsigned char type)
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: name(name), ino(ino), type(type) { }
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};
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typedef vector<DirEntry> DirEntries;
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DirEntries readDirectory(const Path & path);
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unsigned char getFileType(const Path & path);
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/* Read the contents of a file into a string. */
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string readFile(int fd);
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string readFile(const Path & path, bool drain = false);
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/* Write a string to a file. */
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void writeFile(const Path & path, const string & s);
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/* Read a line from a file descriptor. */
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string readLine(int fd);
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/* Write a line to a file descriptor. */
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void writeLine(int fd, string s);
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/* Delete a path; i.e., in the case of a directory, it is deleted
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recursively. It's not an error if the path does not exist. The
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second variant returns the number of bytes and blocks freed. */
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void deletePath(const Path & path);
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void deletePath(const Path & path, unsigned long long & bytesFreed);
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/* Create a temporary directory. */
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Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix",
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bool includePid = true, bool useGlobalCounter = true, mode_t mode = 0755);
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/* Return the path to $XDG_CACHE_HOME/.cache. */
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Path getCacheDir();
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/* Create a directory and all its parents, if necessary. Returns the
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list of created directories, in order of creation. */
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Paths createDirs(const Path & path);
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/* Create a symlink. */
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void createSymlink(const Path & target, const Path & link);
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/* Atomically create or replace a symlink. */
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void replaceSymlink(const Path & target, const Path & link);
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/* Wrappers arount read()/write() that read/write exactly the
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requested number of bytes. */
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void readFull(int fd, unsigned char * buf, size_t count);
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void writeFull(int fd, const unsigned char * buf, size_t count, bool allowInterrupts = true);
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void writeFull(int fd, const string & s, bool allowInterrupts = true);
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MakeError(EndOfFile, Error)
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/* Read a file descriptor until EOF occurs. */
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string drainFD(int fd);
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/* Automatic cleanup of resources. */
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template <class T>
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struct AutoDeleteArray
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{
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T * p;
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AutoDeleteArray(T * p) : p(p) { }
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~AutoDeleteArray()
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{
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delete [] p;
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}
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};
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class AutoDelete
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{
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Path path;
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bool del;
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bool recursive;
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public:
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AutoDelete();
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AutoDelete(const Path & p, bool recursive = true);
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~AutoDelete();
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void cancel();
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void reset(const Path & p, bool recursive = true);
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operator Path() const { return path; }
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};
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class AutoCloseFD
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{
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int fd;
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void close();
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public:
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AutoCloseFD();
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AutoCloseFD(int fd);
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AutoCloseFD(const AutoCloseFD & fd) = delete;
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AutoCloseFD(AutoCloseFD&& fd);
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~AutoCloseFD();
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AutoCloseFD& operator =(const AutoCloseFD & fd) = delete;
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AutoCloseFD& operator =(AutoCloseFD&& fd);
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int get() const;
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explicit operator bool() const;
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int release();
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};
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class Pipe
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{
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public:
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AutoCloseFD readSide, writeSide;
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void create();
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};
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class AutoCloseDir
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{
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DIR * dir;
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public:
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AutoCloseDir();
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AutoCloseDir(DIR * dir);
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~AutoCloseDir();
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void operator =(DIR * dir);
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operator DIR *();
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void close();
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};
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class Pid
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{
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pid_t pid;
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bool separatePG;
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int killSignal;
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public:
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Pid();
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Pid(pid_t pid);
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~Pid();
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void operator =(pid_t pid);
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operator pid_t();
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void kill(bool quiet = false);
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int wait(bool block);
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void setSeparatePG(bool separatePG);
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void setKillSignal(int signal);
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pid_t release();
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};
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/* Kill all processes running under the specified uid by sending them
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a SIGKILL. */
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void killUser(uid_t uid);
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/* Fork a process that runs the given function, and return the child
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pid to the caller. */
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struct ProcessOptions
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{
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string errorPrefix;
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bool dieWithParent;
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bool runExitHandlers;
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bool allowVfork;
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ProcessOptions() : errorPrefix("error: "), dieWithParent(true), runExitHandlers(false), allowVfork(true) { };
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};
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pid_t startProcess(std::function<void()> fun, const ProcessOptions & options = ProcessOptions());
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/* Run a program and return its stdout in a string (i.e., like the
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shell backtick operator). */
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string runProgram(Path program, bool searchPath = false,
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const Strings & args = Strings(), const string & input = "");
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class ExecError : public Error
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{
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public:
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int status;
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template<typename... Args>
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ExecError(int status, Args... args)
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: Error(args...), status(status)
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{ }
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};
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/* Convert a list of strings to a null-terminated vector of char
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*'s. The result must not be accessed beyond the lifetime of the
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list of strings. */
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std::vector<char *> stringsToCharPtrs(const Strings & ss);
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/* Close all file descriptors except stdin, stdout, stderr, and those
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listed in the given set. Good practice in child processes. */
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void closeMostFDs(const set<int> & exceptions);
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/* Set the close-on-exec flag for the given file descriptor. */
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void closeOnExec(int fd);
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/* Restore default handling of SIGPIPE, otherwise some programs will
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randomly say "Broken pipe". */
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void restoreSIGPIPE();
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/* User interruption. */
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extern volatile sig_atomic_t _isInterrupted;
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extern thread_local bool interruptThrown;
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void _interrupted();
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void inline checkInterrupt()
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{
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if (_isInterrupted) _interrupted();
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}
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MakeError(Interrupted, BaseError)
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/* String tokenizer. */
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template<class C> C tokenizeString(const string & s, const string & separators = " \t\n\r");
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/* Concatenate the given strings with a separator between the
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elements. */
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string concatStringsSep(const string & sep, const Strings & ss);
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string concatStringsSep(const string & sep, const StringSet & ss);
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/* Remove trailing whitespace from a string. */
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string chomp(const string & s);
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/* Remove whitespace from the start and end of a string. */
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string trim(const string & s, const string & whitespace = " \n\r\t");
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/* Replace all occurrences of a string inside another string. */
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string replaceStrings(const std::string & s,
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const std::string & from, const std::string & to);
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/* Convert the exit status of a child as returned by wait() into an
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error string. */
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string statusToString(int status);
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bool statusOk(int status);
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/* Parse a string into an integer. */
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template<class N> bool string2Int(const string & s, N & n)
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{
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if (string(s, 0, 1) == "-" && !std::numeric_limits<N>::is_signed)
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return false;
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std::istringstream str(s);
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str >> n;
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return str && str.get() == EOF;
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}
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/* Parse a string into a float. */
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template<class N> bool string2Float(const string & s, N & n)
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{
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std::istringstream str(s);
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str >> n;
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return str && str.get() == EOF;
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}
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/* Return true iff `s' starts with `prefix'. */
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bool hasPrefix(const string & s, const string & prefix);
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/* Return true iff `s' ends in `suffix'. */
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bool hasSuffix(const string & s, const string & suffix);
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/* Convert a string to lower case. */
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std::string toLower(const std::string & s);
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/* Escape a string that contains octal-encoded escape codes such as
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used in /etc/fstab and /proc/mounts (e.g. "foo\040bar" decodes to
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"foo bar"). */
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string decodeOctalEscaped(const string & s);
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/* Exception handling in destructors: print an error message, then
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ignore the exception. */
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void ignoreException();
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/* Some ANSI escape sequences. */
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#define ANSI_NORMAL "\e[0m"
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#define ANSI_BOLD "\e[1m"
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#define ANSI_RED "\e[31;1m"
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/* Filter out ANSI escape codes from the given string. If ‘nixOnly’ is
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set, only filter escape codes generated by Nixpkgs' stdenv (used to
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denote nesting etc.). */
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string filterANSIEscapes(const string & s, bool nixOnly = false);
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/* Base64 encoding/decoding. */
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string base64Encode(const string & s);
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string base64Decode(const string & s);
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/* Get a value for the specified key from an associate container, or a
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default value if the key doesn't exist. */
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template <class T>
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string get(const T & map, const string & key, const string & def = "")
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{
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auto i = map.find(key);
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return i == map.end() ? def : i->second;
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}
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/* Call ‘failure’ with the current exception as argument. If ‘failure’
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throws an exception, abort the program. */
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void callFailure(const std::function<void(std::exception_ptr exc)> & failure,
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std::exception_ptr exc = std::current_exception());
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/* Evaluate the function ‘f’. If it returns a value, call ‘success’
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with that value as its argument. If it or ‘success’ throws an
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exception, call ‘failure’. If ‘failure’ throws an exception, abort
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the program. */
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template<class T>
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void sync2async(
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const std::function<void(T)> & success,
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const std::function<void(std::exception_ptr exc)> & failure,
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const std::function<T()> & f)
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{
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try {
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success(f());
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} catch (...) {
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callFailure(failure);
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}
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}
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/* Call the function ‘success’. If it throws an exception, call
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‘failure’. If that throws an exception, abort the program. */
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template<class T>
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void callSuccess(
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const std::function<void(T)> & success,
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const std::function<void(std::exception_ptr exc)> & failure,
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T && arg)
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{
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try {
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success(arg);
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} catch (...) {
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callFailure(failure);
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}
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}
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/* A variant of std::istringstream that doesn't copy its string
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argument. This is useful for large strings. The caller must ensure
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that the string object is not destroyed while it's referenced by
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this object. */
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class istringbuf_nocopy : public std::streambuf
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{
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const std::string & s;
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decltype(s.size()) off;
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decltype(s.size()) size;
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public:
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istringbuf_nocopy(const std::string & s) : s{s}, off{0}, size{s.size()}
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{
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}
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private:
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int_type underflow()
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{
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if (off == size)
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return traits_type::eof();
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return traits_type::to_int_type(s[off]);
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}
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int_type uflow()
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{
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if (off == size)
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return traits_type::eof();
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return traits_type::to_int_type(s[off++]);
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}
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int_type pbackfail(int_type ch)
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{
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if (off == 0 || (ch != traits_type::eof() && ch != s[off - 1]))
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return traits_type::eof();
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return traits_type::to_int_type(s[--off]);
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}
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std::streamsize showmanyc()
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{
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return size - off;
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}
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};
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struct istringstream_nocopy : public std::iostream
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{
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istringbuf_nocopy buf;
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istringstream_nocopy(const std::string & s) : std::iostream(&buf), buf(s) {};
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};
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}
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