lix/src/libstore/store.hh

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#ifndef __STORE_H
#define __STORE_H
#include <string>
#include "hash.hh"
#include "db.hh"
using namespace std;
/* A substitute is a program invocation that constructs some store
path (typically by fetching it from somewhere, e.g., from the
network). */
struct Substitute
{
/* Program to be executed to create the store path. Must be in
the output path of `storeExpr'. */
Path program;
/* Extra arguments to be passed to the program (the first argument
is the store path to be substituted). */
Strings args;
bool operator == (const Substitute & sub);
};
typedef list<Substitute> Substitutes;
/* Open the database environment. */
void openDB();
/* Create the required database tables. */
void initDB();
/* Get a transaction object. */
void createStoreTransaction(Transaction & txn);
/* Copy a path recursively. */
void copyPath(const Path & src, const Path & dst);
/* Register a successor. This function accepts a transaction handle
so that it can be enclosed in an atomic operation with calls to
registerValidPath(). This must be atomic, since if we register a
successor for a derivation without registering the paths built in
the derivation, we have a successor with dangling pointers, and if
we do it in reverse order, we can get an obstructed build (since to
rebuild the successor, the outputs paths must not exist). */
void registerSuccessor(const Transaction & txn,
const Path & srcPath, const Path & sucPath);
/* Remove a successor mapping. */
void unregisterSuccessor(const Path & srcPath);
/* Return the predecessors of the Nix expression stored at the given
path. */
bool querySuccessor(const Path & srcPath, Path & sucPath);
/* Return the predecessors of the Nix expression stored at the given
path. */
Paths queryPredecessors(const Path & sucPath);
/* Register a substitute. */
typedef list<pair<Path, Substitute> > SubstitutePairs;
void registerSubstitutes(const Transaction & txn,
const SubstitutePairs & subPairs);
/* Return the substitutes expression for the given path. */
Substitutes querySubstitutes(const Path & srcPath);
/* Deregister all substitutes. */
void clearSubstitutes();
/* Register the validity of a path. */
void registerValidPath(const Transaction & txn, const Path & path);
/* Throw an exception if `path' is not directly in the Nix store. */
void assertStorePath(const Path & path);
/* Checks whether a path is valid. */
bool isValidPath(const Path & path);
/* Constructs a unique store path name. */
Path makeStorePath(const string & type,
* Removed the `id' attribute hack. * Formalise the notion of fixed-output derivations, i.e., derivations for which a cryptographic hash of the output is known in advance. Changes to such derivations should not propagate upwards through the dependency graph. Previously this was done by specifying the hash component of the output path through the `id' attribute, but this is insecure since you can lie about it (i.e., you can specify any hash and then produce a completely different output). Now the responsibility for checking the output is moved from the builder to Nix itself. A fixed-output derivation can be created by specifying the `outputHash' and `outputHashAlgo' attributes, the latter taking values `md5', `sha1', and `sha256', and the former specifying the actual hash in hexadecimal or in base-32 (auto-detected by looking at the length of the attribute value). MD5 is included for compatibility but should be considered deprecated. * Removed the `drvPath' pseudo-attribute in derivation results. It's no longer necessary. * Cleaned up the support for multiple output paths in derivation store expressions. Each output now has a unique identifier (e.g., `out', `devel', `docs'). Previously there was no way to tell output paths apart at the store expression level. * `nix-hash' now has a flag `--base32' to specify that the hash should be printed in base-32 notation. * `fetchurl' accepts parameters `sha256' and `sha1' in addition to `md5'. * `nix-prefetch-url' now prints out a SHA-1 hash in base-32. (TODO: a flag to specify the hash.)
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const Hash & hash, const string & suffix);
/* Copy the contents of a path to the store and register the validity
the resulting path. The resulting path is returned. */
Path addToStore(const Path & srcPath);
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/* Like addToStore, but the contents written to the output path is a
regular file containing the given string. */
Path addTextToStore(const string & suffix, const string & s);
/* Delete a value from the nixStore directory. */
void deleteFromStore(const Path & path);
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void verifyStore();
#endif /* !__STORE_H */