diff options
Diffstat (limited to 'src/store.cc')
-rw-r--r-- | src/store.cc | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/src/store.cc b/src/store.cc new file mode 100644 index 000000000..68a1cd1e2 --- /dev/null +++ b/src/store.cc @@ -0,0 +1,132 @@ +#include <iostream> + +#include <sys/types.h> +#include <sys/wait.h> + +#include "store.hh" +#include "globals.hh" +#include "db.hh" +#include "archive.hh" + + +struct CopySink : DumpSink +{ + int fd; + virtual void operator () (const unsigned char * data, unsigned int len) + { + if (write(fd, (char *) data, len) != (ssize_t) len) + throw SysError("writing to child"); + } +}; + + +struct CopySource : RestoreSource +{ + int fd; + virtual void operator () (const unsigned char * data, unsigned int len) + { + ssize_t res = read(fd, (char *) data, len); + if (res == -1) + throw SysError("reading from parent"); + if (res != (ssize_t) len) + throw Error("not enough data available on parent"); + } +}; + + +void copyPath(string src, string dst) +{ + /* Unfortunately C++ doesn't support coprocedures, so we have no + nice way to chain CopySink and CopySource together. Instead we + fork off a child to run the sink. (Fork-less platforms should + use a thread). */ + + /* Create a pipe. */ + int fds[2]; + if (pipe(fds) == -1) throw SysError("creating pipe"); + + /* Fork. */ + pid_t pid; + switch (pid = fork()) { + + case -1: + throw SysError("unable to fork"); + + case 0: /* child */ + try { + close(fds[1]); + CopySource source; + source.fd = fds[0]; + restorePath(dst, source); + _exit(0); + } catch (exception & e) { + cerr << "error: " << e.what() << endl; + } + _exit(1); + } + + close(fds[0]); + + /* Parent. */ + + CopySink sink; + sink.fd = fds[1]; + dumpPath(src, sink); + + /* Wait for the child to finish. */ + int status; + if (waitpid(pid, &status, 0) != pid) + throw SysError("waiting for child"); + + if (!WIFEXITED(status) || WEXITSTATUS(status) != 0) + throw Error("cannot copy file: child died"); +} + + +void addToStore(string srcPath, string & dstPath, Hash & hash) +{ + srcPath = absPath(srcPath); + + hash = hashPath(srcPath); + + string path; + if (queryDB(nixDB, dbRefs, hash, path)) { + debug((string) hash + " already known"); + dstPath = path; + return; + } + + string baseName = baseNameOf(srcPath); + dstPath = nixStore + "/" + (string) hash + "-" + baseName; + + copyPath(srcPath, dstPath); + + setDB(nixDB, dbRefs, hash, dstPath); +} + + +void deleteFromStore(const string & path) +{ + string prefix = nixStore + "/"; + if (string(path, 0, prefix.size()) != prefix) + throw Error(format("path %1% is not in the store") % path); + deletePath(path); +// delDB(nixDB, dbRefs, hash); +} + + +string queryFromStore(Hash hash) +{ + string fn, url; + + if (queryDB(nixDB, dbRefs, hash, fn)) { + + /* Verify that the file hasn't changed. !!! race !!! slow */ + if (hashPath(fn) != hash) + throw Error("file " + fn + " is stale"); + + return fn; + } + + throw Error(format("don't know a path with hash `%1%'") % (string) hash); +} |