Commit graph

17 commits

Author SHA1 Message Date
Eelco Dolstra c505702265 * Fix and simplify the garbage collector (it's still not concurrent,
though).  In particular it's now much easier to register a GC root.
  Just place a symlink to whatever store path it is that you want to
  keep in /nix/var/nix/gcroots.
2005-01-27 15:21:29 +00:00
Eelco Dolstra a24b78e9f1 * Maintain the references/referers relation also for derivations.
This simplifies garbage collection and `nix-store --query
  --requisites' since we no longer need to treat derivations
  specially.

* Better maintaining of the invariants, e.g., setReferences() can only
  be called on a valid/substitutable path.
2005-01-25 21:28:25 +00:00
Eelco Dolstra 2a2756b856 * Simplification: registerSubstitutes -> registerSubstitute. We no
longer need the former since there we no longer have the
  substitutes-rev table (which triggered a O(n^2) cost in updating
  them).
2005-01-25 20:27:40 +00:00
Eelco Dolstra 6a0a2d5593 * Terminology fixes. 2005-01-20 16:01:07 +00:00
Eelco Dolstra e0f4e587c3 * Nix-store queries --references' and referers' to query the pointer
graph.  That is, `nix-store --query --references PATH' shows the set
  of paths referenced by PATH, and `nix-store --query --referers PATH'
  shows the set of paths referencing PATH.
2005-01-19 16:59:56 +00:00
Eelco Dolstra 96de272b48 * Renamed normalise.cc' -> build.cc', `storeexprs.cc' ->
`derivations.cc', etc.
* Store the SHA-256 content hash of store paths in the database after
  they have been built/added.  This is so that we can check whether
  the store has been messed with (a la `rpm --verify').
* When registering path validity, verify that the closure property
  holds.
2005-01-19 16:39:47 +00:00
Eelco Dolstra 863dcff6c5 * Started removing closure store expressions, i.e., the explicit
representation of closures as ATerms in the Nix store.  Instead, the
  file system pointer graph is now stored in the Nix database.  This
  has many advantages:

  - It greatly simplifies the implementation (we can drop the notion
    of `successors', and so on).

  - It makes registering roots for the garbage collector much easier.
    Instead of specifying the closure expression as a root, you can
    simply specify the store path that must be retained as a root.
    This could not be done previously, since there was no way to find
    the closure store expression containing a given store path.
    
  - Better traceability: it is now possible to query what paths are
    referenced by a path, and what paths refer to a path.
2005-01-19 11:16:11 +00:00
Eelco Dolstra f3dc231250 * 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.)
2005-01-17 16:55:19 +00:00
Eelco Dolstra 9530cc3170 * Start move towards SHA-256 hashes instead of MD5.
* Start cleaning up unique store path generation (they weren't always
  unique; in particular the suffix ("-aterm-2.2", "-builder.sh") was
  not part of the hash, therefore changes to the suffix would cause
  multiple store objects with the same hash).
2005-01-14 13:51:38 +00:00
Eelco Dolstra fa9259f5f5 * Simplify the substitute mechanism:
- Drop the store expression.  So now a substitute is just a
    command-line invocation (a program name + arguments).  If you
    register a substitute you are responsible for registering the
    expression that built it (if any) as a root of the garbage
    collector.
  - Drop the substitutes-rev DB table.
2004-12-20 13:43:32 +00:00
Eelco Dolstra 5c443b6550 * Main the `substitutes-rev' table again, but now in a way that
doesn't take \Theta(n^2) space/time complexity.
2004-08-31 16:13:10 +00:00
Eelco Dolstra 91dc023665 * Added a switch `--fallback'. From the manual:
Whenever Nix attempts to realise a derivation for which a closure is
  already known, but this closure cannot be realised, fall back on
  normalising the derivation.

  The most common scenario in which this is useful is when we have
  registered substitutes in order to perform binary distribution from,
  say, a network repository.  If the repository is down, the
  realisation of the derivation will fail.  When this option is
  specified, Nix will build the derivation instead.  Thus, binary
  installation falls back on a source installation.  This option is
  not the default since it is generally not desirable for a transient
  failure in obtaining the substitutes to lead to a full build from
  source (with the related consumption of resources).
2004-06-28 10:42:57 +00:00
Eelco Dolstra daf0a923c7 * Wrap calls to registerSubstitute() in a single transaction to
improve throughput.
* Don't build the `substitute-rev' table for now, since it caused
  Theta(N^2) time and log file consumption when adding N substitutes.
  Maybe we can do without it.
2004-06-21 07:38:17 +00:00
Eelco Dolstra 112ee89501 * Re-enable support for substitutes in the normaliser.
* A better substitute mechanism.

  Instead of generating a store expression for each store path for
  which we have a substitute, we can have a single store expression
  that builds a generic program that is invoked to build the desired
  store path, which is passed as an argument.

  This means that operations like `nix-pull' only produce O(1) files
  instead of O(N) files in the store when registering N substitutes.
  (It consumes O(N) database storage, of course, but that's not a
  performance problem).

* Added a test for the substitute mechanism.
  
* `nix-store --substitute' reads the substitutes from standard input,
  instead of from the command line.  This prevents us from running
  into the kernel's limit on command line length.
2004-06-20 19:17:54 +00:00
Eelco Dolstra a4d2b22c8c * Be stricter in verifying store paths. 2004-04-14 08:08:55 +00:00
Eelco Dolstra ab0bc4999a * Maintain integrity of the substitute and successor mappings when
deleting a path in the store.
* Allow absolute paths in Nix expressions.
* Get nix-prefetch-url to work again.
* Various other fixes.
2003-11-22 18:45:56 +00:00
Eelco Dolstra 9f0f020929 * libnix -> libstore. 2003-11-18 10:55:27 +00:00
Renamed from src/libnix/store.hh (Browse further)