lix/src/globals.hh
2003-06-17 15:45:43 +00:00

65 lines
1.7 KiB
C++

#ifndef __GLOBALS_H
#define __GLOBALS_H
#include <string>
using namespace std;
/* Database names. */
/* dbRefs :: Hash -> FileName
Maintains a mapping from hashes to filenames within the NixValues
directory. This mapping is for performance only; it can be
reconstructed unambiguously. The reason is that names in this
directory are not printed hashes but also might carry some
descriptive element (e.g., "aterm-2.0-ae749a..."). Without this
mapping, looking up a value would take O(n) time because we would
need to read the entire directory. */
extern string dbRefs;
/* dbNFs :: Hash -> Hash
Each pair (h1, h2) in this mapping records the fact that the normal
form of an expression with hash h1 is Hash(h2).
TODO: maybe this should be that the normal form of an expression
with hash h1 is an expression with hash h2; this would be more
general, but would require us to store lots of small expressions in
the file system just to support the caching mechanism.
*/
extern string dbNFs;
/* dbNetSources :: Hash -> URL
Each pair (hash, url) in this mapping states that the value
identified by hash can be obtained by fetching the value pointed
to by url.
TODO: this should be Hash -> [URL]
TODO: factor this out into a separate tool? */
extern string dbNetSources;
/* Path names. */
/* nixValues is the directory where all Nix values (both files and
directories, and both normal and non-normal forms) live. */
extern string nixValues;
/* nixLogDir is the directory where we log evaluations. */
extern string nixLogDir;
/* nixDB is the file name of the Berkeley DB database where we
maintain the dbXXX mappings. */
extern string nixDB;
/* Initialize the databases. */
void initDB();
#endif /* !__GLOBALS_H */