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#ifndef __GLOBALS_H
#define __GLOBALS_H
#include <string>
using namespace std;
/* Database names. */
/* dbHash2Paths :: Hash -> [Path]
Maintains a mapping from hashes to lists of paths. This is what we
use to resolve Hash(hash) content descriptors. */
extern string dbHash2Paths;
/* dbSuccessors :: Hash -> Hash
Each pair (h1, h2) in this mapping records the fact that a
successor of an fstate expression with hash h1 is stored in a file
with hash h2.
Note that a term $y$ is successor of $x$ iff there exists a
sequence of rewrite steps that rewrites $x$ into $y$.
Also note that instead of a successor, $y$ can be any term
equivalent to $x$, that is, reducing to the same result, as long as
$x$ is equal to or a successor of $y$. (This is useful, e.g., for
shared derivate caching over the network).
*/
extern string dbSuccessors;
/* dbSubstitutes :: Hash -> [Hash]
Each pair $(h, [hs])$ tells Nix that it can realise any of the
fstate expressions referenced by the hashes in $hs$ to obtain a Nix
archive that, when unpacked, will produce a path with hash $h$.
The main purpose of this is for distributed caching of derivates.
One system can compute a derivate with hash $h$ and put it on a
website (as a Nix archive), for instance, and then another system
can register a substitute for that derivate. The substitute in
this case might be an fstate expression that fetches the Nix
archive.
*/
extern string dbSubstitutes;
/* Path names. */
/* nixStore is the directory where we generally store atomic and
derived files. */
extern string nixStore;
extern string nixDataDir; /* !!! fix */
/* nixLogDir is the directory where we log various operations. */
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 */
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