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authorLudovic Courtès <ludo@gnu.org>2014-12-17 23:00:42 +0100
committerLudovic Courtès <ludo@gnu.org>2014-12-19 22:47:37 +0100
commit36457566f9917dc7c0c348d012816a2ca333ef1b (patch)
tree6f1d22a195ea2483b9ce539227d65e8e2a9c137d /nix/libutil/util.hh
parent2c7ee1672029aa43afb509af5b5f7261244fa2d1 (diff)
Merge branch 'nix' into 'master'.
Diffstat (limited to 'nix/libutil/util.hh')
-rw-r--r--nix/libutil/util.hh349
1 files changed, 349 insertions, 0 deletions
diff --git a/nix/libutil/util.hh b/nix/libutil/util.hh
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@@ -0,0 +1,349 @@
+#pragma once
+
+#include "types.hh"
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <dirent.h>
+#include <unistd.h>
+#include <signal.h>
+
+#include <cstdio>
+
+
+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<class T, class A>
+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 <class T>
+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<int> & 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<class C> 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<class N> bool string2Int(const string & s, N & n)
+{
+ std::istringstream str(s);
+ str >> n;
+ return str && str.get() == EOF;
+}
+
+template<class N> 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();
+
+
+}