From 5eaf644c99c78ed89b2cab1d10d630435fd55d28 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Wed, 3 Dec 2008 17:30:32 +0000 Subject: [PATCH] * A simple API for parsing NAR archives. --- src/libutil/archive.cc | 89 +++++++++++++++++++++++++++++----------- src/libutil/archive.hh | 13 ++++++ src/libutil/serialise.hh | 4 +- 3 files changed, 80 insertions(+), 26 deletions(-) diff --git a/src/libutil/archive.cc b/src/libutil/archive.cc index a8e018b69..30b94951b 100644 --- a/src/libutil/archive.cc +++ b/src/libutil/archive.cc @@ -129,10 +129,11 @@ static void skipGeneric(Source & source) } -static void restore(const Path & path, Source & source); +static void parse(ParseSink & sink, Source & source, const Path & path); -static void restoreEntry(const Path & path, Source & source) + +static void parseEntry(ParseSink & sink, Source & source, const Path & path) { string s, name; @@ -150,7 +151,7 @@ static void restoreEntry(const Path & path, Source & source) name = readString(source); } else if (s == "node") { if (s == "") throw badArchive("entry name missing"); - restore(path + "/" + name, source); + parse(sink, source, path + "/" + name); } else { throw badArchive("unknown field " + s); skipGeneric(source); @@ -159,7 +160,7 @@ static void restoreEntry(const Path & path, Source & source) } -static void restoreContents(int fd, const Path & path, Source & source) +static void parseContents(ParseSink & sink, Source & source, const Path & path) { unsigned int size = readInt(source); unsigned int left = size; @@ -170,7 +171,7 @@ static void restoreContents(int fd, const Path & path, Source & source) unsigned int n = sizeof(buf); if (n > left) n = left; source(buf, n); - writeFull(fd, buf, n); + sink.receiveContents(buf, n); left -= n; } @@ -178,7 +179,7 @@ static void restoreContents(int fd, const Path & path, Source & source) } -static void restore(const Path & path, Source & source) +static void parse(ParseSink & sink, Source & source, const Path & path) { string s; @@ -186,7 +187,6 @@ static void restore(const Path & path, Source & source) if (s != "(") throw badArchive("expected open tag"); enum { tpUnknown, tpRegular, tpDirectory, tpSymlink } type = tpUnknown; - AutoCloseFD fd; while (1) { checkInterrupt(); @@ -204,15 +204,12 @@ static void restore(const Path & path, Source & source) if (t == "regular") { type = tpRegular; - fd = open(path.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0666); - if (fd == -1) - throw SysError("creating file " + path); + sink.createRegularFile(path); } else if (t == "directory") { + sink.createDirectory(path); type = tpDirectory; - if (mkdir(path.c_str(), 0777) == -1) - throw SysError("creating directory " + path); } else if (t == "symlink") { @@ -224,42 +221,86 @@ static void restore(const Path & path, Source & source) } else if (s == "contents" && type == tpRegular) { - restoreContents(fd, path, source); + parseContents(sink, source, path); } else if (s == "executable" && type == tpRegular) { readString(source); - struct stat st; - if (fstat(fd, &st) == -1) - throw SysError("fstat"); - if (fchmod(fd, st.st_mode | (S_IXUSR | S_IXGRP | S_IXOTH)) == -1) - throw SysError("fchmod"); + sink.isExecutable(); } else if (s == "entry" && type == tpDirectory) { - restoreEntry(path, source); + parseEntry(sink, source, path); } else if (s == "target" && type == tpSymlink) { string target = readString(source); - if (symlink(target.c_str(), path.c_str()) == -1) - throw SysError("creating symlink " + path); + sink.createSymlink(path, target); } else { throw badArchive("unknown field " + s); skipGeneric(source); } - } } -void restorePath(const Path & path, Source & source) +void parseDump(ParseSink & sink, Source & source) { if (readString(source) != archiveVersion1) throw badArchive("expected Nix archive"); - restore(path, source); + parse(sink, source, ""); +} + + +struct RestoreSink : ParseSink +{ + Path dstPath; + AutoCloseFD fd; + + void createDirectory(const Path & path) + { + Path p = dstPath + path; + if (mkdir(p.c_str(), 0777) == -1) + throw SysError(format("creating directory `%1%'") % p); + }; + + void createRegularFile(const Path & path) + { + Path p = dstPath + path; + fd = open(p.c_str(), O_CREAT | O_EXCL | O_WRONLY, 0666); + if (fd == -1) throw SysError(format("creating file `%1%'") % p); + } + + void isExecutable() + { + struct stat st; + if (fstat(fd, &st) == -1) + throw SysError("fstat"); + if (fchmod(fd, st.st_mode | (S_IXUSR | S_IXGRP | S_IXOTH)) == -1) + throw SysError("fchmod"); + } + + void receiveContents(unsigned char * data, unsigned int len) + { + writeFull(fd, data, len); + } + + void createSymlink(const Path & path, const string & target) + { + Path p = dstPath + path; + if (symlink(target.c_str(), p.c_str()) == -1) + throw SysError(format("creating symlink `%1%'") % p); + } +}; + + +void restorePath(const Path & path, Source & source) +{ + RestoreSink sink; + sink.dstPath = path; + parseDump(sink, source); } diff --git a/src/libutil/archive.hh b/src/libutil/archive.hh index 5f85e1beb..06f09cd1e 100644 --- a/src/libutil/archive.hh +++ b/src/libutil/archive.hh @@ -56,6 +56,19 @@ extern PathFilter defaultPathFilter; void dumpPath(const Path & path, Sink & sink, PathFilter & filter = defaultPathFilter); +struct ParseSink +{ + virtual void createDirectory(const Path & path) { }; + + virtual void createRegularFile(const Path & path) { }; + virtual void isExecutable() { }; + virtual void receiveContents(unsigned char * data, unsigned int len) { }; + + virtual void createSymlink(const Path & path, const string & target) { }; +}; + +void parseDump(ParseSink & sink, Source & source); + void restorePath(const Path & path, Source & source); diff --git a/src/libutil/serialise.hh b/src/libutil/serialise.hh index 75d17bc60..5746c3c2f 100644 --- a/src/libutil/serialise.hh +++ b/src/libutil/serialise.hh @@ -80,9 +80,9 @@ struct StringSink : Sink /* A source that reads data from a string. */ struct StringSource : Source { - string & s; + const string & s; unsigned int pos; - StringSource(string & _s) : s(_s), pos(0) { } + StringSource(const string & _s) : s(_s), pos(0) { } virtual void operator () (unsigned char * data, unsigned int len) { s.copy((char *) data, len, pos);