Commit graph

534 commits

Author SHA1 Message Date
Eelco Dolstra 229567293c Shut up a compiler warning 2013-05-16 17:48:19 +02:00
Eelco Dolstra 804709706c Fix building against Bison 2.6 2013-03-14 18:31:08 +01:00
Eelco Dolstra c56bc3d81c Make sure that thunks are restored properly if an exception occurs
Fixes Hydra bug #67.
2013-03-14 17:21:13 +01:00
Eelco Dolstra bdd4646338 Revert "Prevent config.h from being clobbered"
This reverts commit 28bba8c44f.
2013-03-08 01:24:59 +01:00
Eelco Dolstra 28bba8c44f Prevent config.h from being clobbered 2013-03-07 23:55:55 +01:00
Eelco Dolstra 5f18cd2e84 Make "${./path} ..." evaluate to a string, not a path
Wacky string coercion semantics caused expressions like

  exec = "${./my-script} params...";

to evaluate to a path (‘/path/my-script params’), because
anti-quotations are desuged to string concatenation:

  exec = ./my-script + " params...";

By constrast, adding a space at the start would yield a string as
expected:

  exec = " ${./my-script} params...";

Now the first example also evaluates to a string.
2013-02-08 20:04:04 +01:00
Eelco Dolstra 52172607cf Rename "hash" to "hashString" and handle SHA-1 2013-02-08 19:36:23 +01:00
Marc Weber 01a5ea9914 experimental/hash
adding primop function calculating hash of a string

Signed-off-by: Marc Weber <marco-oweber@gmx.de>
2013-02-08 19:26:34 +01:00
Stuart Pernsteiner a9045c727f fix use-after-free bug in mkString(Value&, Symbol&) 2012-12-13 11:13:20 +01:00
Eelco Dolstra 3100b29fc5 Tiny optimisation in the filter primop 2012-12-04 17:22:20 +01:00
Eelco Dolstra 8eed07cda4 nix-env -q --out-path: Support multiple outputs
We now print all output paths of a package, e.g.

  openssl-1.0.0i  bin=/nix/store/gq2mvh0wb9l90djvsagln3aqywqmr6vl-openssl-1.0.0i-bin;man=/nix/store/7zwf5r5hsdarl3n86dasvb4chm2xzw9n-openssl-1.0.0i-man;/nix/store/cj7xvk7fjp9q887359j75pw3pzjfmqf1-openssl-1.0.0i

or (in XML mode)

  <item attrPath="openssl" name="openssl-1.0.0i" system="x86_64-linux">
    <output name="bin" path="/nix/store/gq2mvh0wb9l90djvsagln3aqywqmr6vl-openssl-1.0.0i-bin" />
    <output name="man" path="/nix/store/7zwf5r5hsdarl3n86dasvb4chm2xzw9n-openssl-1.0.0i-man" />
    <output name="out" path="/nix/store/cj7xvk7fjp9q887359j75pw3pzjfmqf1-openssl-1.0.0i" />
  </item>
2012-11-28 13:49:44 +01:00
Eelco Dolstra 6c98e6a5de Optionally ignore null-valued derivation attributes
This allows adding attributes like

  attr = if stdenv.system == "bla" then something else null;

without changing the resulting derivation on non-<bla> platforms.

We once considered adding a special "ignore" value for this purpose,
but using null seems more elegant.
2012-11-27 15:01:32 +01:00
Eelco Dolstra 8b8ee53bc7 Add builtin constants ‘langVersion’ and ‘nixVersion’
The integer constant ‘langVersion’ denotes the current language
version.  It gets increased every time a language feature is
added/changed/removed.  It's currently 1.

The string constant ‘nixVersion’ contains the current Nix version,
e.g. "1.2pre2980_9de6bc5".
2012-11-27 13:29:55 +01:00
Eelco Dolstra 408a7bfac1 nix-instantiate: Fix read-only evaluation 2012-11-26 17:41:10 +01:00
Eelco Dolstra 17dc306aa3 Revert "prim_toPath: Actually make the string a path"
This reverts commit 2980d1fba9.  It
causes a regression in NixOS evaluation:

string `/nix/store/ya3s5gmj3b28170fpbjhgsk8wzymkpa1-pommed-1.39/etc/pommed.conf' cannot refer to other paths
2012-11-15 23:04:34 +01:00
Eelco Dolstra 88164325fa Fix a segfault when auto-calling a "a@{...}" function
Since the called function can return its argument attribute set
(e.g. "a"), the latter should not be allocated on the stack.

Reported by Shea.
2012-11-09 15:09:31 +01:00
Shea Levy 2980d1fba9 prim_toPath: Actually make the string a path 2012-10-23 16:39:35 +02:00
Eelco Dolstra 70f75be199 getDerivation(): Don't always quietly ignore assertion failure
Ignoring assertion failures makes some sense for nix-env -qa, but not
for nix-instantiate/nix-build or hydra-eval-jobs.
2012-10-04 15:22:25 -04:00
Eelco Dolstra 0a7084567f Add a ‘--repair’ flag to nix-instantiate
This allows repairing corrupted derivations and other source files.
2012-10-03 15:09:18 -04:00
Eelco Dolstra 95c74eae26 Allow dashes in identifiers
In Nixpkgs, the attribute in all-packages.nix corresponding to a
package is usually equal to the package name.  However, this doesn't
work if the package contains a dash, which is fairly common.  The
convention is to replace the dash with an underscore (e.g. "dbus-lib"
becomes "dbus_glib"), but that's annoying.  So now dashes are valid in
variable / attribute names, allowing you to write:

  dbus-glib = callPackage ../development/libraries/dbus-glib { };

and

  buildInputs = [ dbus-glib ];

Since we don't have a negation or subtraction operation in Nix, this
is unambiguous.
2012-09-27 15:49:20 -04:00
Eelco Dolstra 76e88871b2 Templatise tokenizeString() 2012-09-19 15:43:23 -04:00
Eelco Dolstra e94806d030 Merge branch 'master' into no-manifests 2012-08-27 11:09:07 -04:00
Eelco Dolstra 767101824a Avoid concatenating lists of one string 2012-08-13 15:10:29 -04:00
Eelco Dolstra e5c589d271 Don't allocate empty lists
This saves about 4 MB when evaluating a NixOS system configuration.
2012-08-13 15:02:09 -04:00
Eelco Dolstra 3e89ef597c Optimise concatenating a list to an empty list
More precisely, in concatLists, if all lists except one are empty,
then just return the non-empty list.  This reduces the number of list
element allocations by 32% when evaluating a NixOS system
configuration.
2012-08-13 14:58:54 -04:00
Eelco Dolstra 9c2d63084b Add a primop ‘elemAt’ to get an element from a list 2012-08-13 13:46:42 -04:00
Eelco Dolstra 198d0338be Add a primop ‘concatLists’
This can serve as a generic efficient list builder.  For instance, the
function ‘catAttrs’ in Nixpkgs can be rewritten from

  attr: l: fold (s: l: if hasAttr attr s then [(getAttr attr s)] ++ l else l) [] l

to

  attr: l: builtins.concatLists (map (s: if hasAttr attr s then [(getAttr attr s)] else []) l)

Statistics before:

  time elapsed: 1.08683
  size of a value: 24
  environments allocated: 1384376 (35809568 bytes)
  list elements: 6946783 (55574264 bytes)
  list concatenations: 37434
  values allocated: 1760440 (42250560 bytes)
  attribute sets allocated: 392040
  right-biased unions: 186334
  values copied in right-biased unions: 591137
  symbols in symbol table: 18273
  number of thunks: 1297673
  number of thunks avoided: 1380759
  number of attr lookups: 430802
  number of primop calls: 628912
  number of function calls: 1333544

Statistics after (including new catAttrs):

  time elapsed: 0.959854
  size of a value: 24
  environments allocated: 1010198 (26829296 bytes)
  list elements: 1984878 (15879024 bytes)
  list concatenations: 30488
  values allocated: 1589760 (38154240 bytes)
  attribute sets allocated: 392040
  right-biased unions: 186334
  values copied in right-biased unions: 591137
  symbols in symbol table: 18274
  number of thunks: 1040925
  number of thunks avoided: 1038428
  number of attr lookups: 438419
  number of primop calls: 474844
  number of function calls: 959366
2012-08-13 01:53:10 -04:00
Eelco Dolstra b9e5b908ed Provide an efficient implementation of ‘elem’
The one in Nixpkgs is O(n^2), this one is O(n).  Big reduction in the
number of list allocations.

Statistics before (on a NixOS system config):

  time elapsed: 1.17982
  size of a value: 24
  environments allocated: 1543334 (39624560 bytes)
  list elements: 9612638 (76901104 bytes)
  list concatenations: 37434
  values allocated: 1854933 (44518392 bytes)
  attribute sets allocated: 392040
  right-biased unions: 186334
  values copied in right-biased unions: 591137
  symbols in symbol table: 18272
  number of thunks: 1392467
  number of thunks avoided: 1507311
  number of attr lookups: 430801
  number of primop calls: 691600
  number of function calls: 1492502

Statistics after:

  time elapsed: 1.08683
  size of a value: 24
  environments allocated: 1384376 (35809568 bytes)
  list elements: 6946783 (55574264 bytes)
  list concatenations: 37434
  values allocated: 1760440 (42250560 bytes)
  attribute sets allocated: 392040
  right-biased unions: 186334
  values copied in right-biased unions: 591137
  symbols in symbol table: 18273
  number of thunks: 1297673
  number of thunks avoided: 1380759
  number of attr lookups: 430802
  number of primop calls: 628912
  number of function calls: 1333544
2012-08-13 01:05:35 -04:00
Eelco Dolstra 4ccd48ce24 Add a "filter" primop
Evaluation of a NixOS configuration spends quite a lot of time in the
"filter" function in Nixpkgs.  As implemented in Nixpkgs, this is a
O(n^2) operation, so it's a good candidate for providing a more
efficient (i.e. primop) implementation.  Using it gives a ~10% speed
increase and a significant reduction in the number of evaluations.

Statistics before (on a NixOS system config):

  time elapsed: 1.3258
  size of a value: 24
  environments allocated: 1980939 (50127080 bytes)
  list elements: 14679308 (117434464 bytes)
  list concatenations: 50828
  values allocated: 2098938 (50374512 bytes)
  attribute sets allocated: 392040
  right-biased unions: 186334
  values copied in right-biased unions: 591137
  symbols in symbol table: 18271
  number of thunks: 1645752
  number of thunks avoided: 1921196
  number of attr lookups: 430798
  number of primop calls: 838807
  number of function calls: 1930107

Statistics after:

  time elapsed: 1.17982
  size of a value: 24
  environments allocated: 1543334 (39624560 bytes)
  list elements: 9612638 (76901104 bytes)
  list concatenations: 37434
  values allocated: 1854933 (44518392 bytes)
  attribute sets allocated: 392040
  right-biased unions: 186334
  values copied in right-biased unions: 591137
  symbols in symbol table: 18272
  number of thunks: 1392467
  number of thunks avoided: 1507311
  number of attr lookups: 430801
  number of primop calls: 691600
  number of function calls: 1492502
2012-08-13 00:28:08 -04:00
Eelco Dolstra 62f72eb9e1 Add some more evaluations stats 2012-08-12 23:41:48 -04:00
Eelco Dolstra e82767910c Add some basic profiling support to the evaluator
Setting the environment variable NIX_COUNT_CALLS to 1 enables some
basic profiling in the evaluator.  It will count calls to functions
and primops as well as evaluations of attributes.

For example, to see where evaluation of a NixOS configuration spends
its time:

$ NIX_SHOW_STATS=1 NIX_COUNT_CALLS=1 ./src/nix-instantiate/nix-instantiate '<nixos>' -A system --readonly-mode
...
calls to 39 primops:
    239532 head
    233962 tail
    191252 hasAttr
...
calls to 1595 functions:
    224157 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:19'
    221767 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:14'
    221767 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/lists.nix:17:10'
...
evaluations of 7088 attributes:
    167377 undefined position
    132459 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/attrsets.nix:119:41'
     47322 `/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/pkgs/lib/attrsets.nix:13:21'
...
2012-08-12 23:29:28 -04:00
Eelco Dolstra 97421eb5ec Refactor settings processing
Put all Nix configuration flags in a Settings object.
2012-07-30 19:55:41 -04:00
Eelco Dolstra 8c79100839 Merge branch 'master' into no-manifests 2012-07-26 15:14:33 -04:00
Shea Levy f5954e2d94 prim_import: When importing .drvs, allocate the intermediate attrset on the heap just in case it escapes the stack frame. 2012-07-25 09:30:17 -04:00
Shea Levy b1112bbef1 import: If the path is a valid .drv file, parse it and generate a derivation attrset.
The generated attrset has drvPath and outPath with the right string context, type 'derivation', outputName with
the right name, all with a list of outputs, and an attribute for each output.

I see three uses for this (though certainly there may be more):

* Using derivations generated by something besides nix-instantiate (e.g. guix)

* Allowing packages provided by channels to be used in nix expressions. If a channel installed a valid deriver
  for each package it provides into the store, then those could be imported and used as dependencies or installed
  in environment.systemPackages, for example.

* Enable hydra to be consistent in how it treats inputs that are outputs of another build. Right now, if an
  input is passed as an argument to the job, it is passed as a derivation, but if it is accessed via NIX_PATH
  (i.e. through the <> syntax), then it is a path that can be imported. This is problematic because the build
  being depended upon may have been built with non-obvious arguments passed to its jobset file. With this
  feature, hydra can just set the name of that input to the path to its drv file in NIX_PATH
2012-07-25 09:30:17 -04:00
Eelco Dolstra b7fd2c2822 Use "#pragma once" to prevent repeated header file inclusion 2012-07-18 14:59:03 -04:00
Eelco Dolstra fe241ece29 Merge branch 'master' into no-manifests 2012-07-18 10:47:59 -04:00
Eelco Dolstra 1217204c81 Remove dead code 2012-07-17 14:07:52 -04:00
Eelco Dolstra a7a43adb79 builtins.storePath: resolve symlinks
Needed for Charon/Hydra interaction.
2012-07-12 18:25:01 -04:00
Eelco Dolstra 6586414bc7 nix-env: Determine which paths have substitutes in parallel 2012-07-11 10:14:06 -04:00
Eelco Dolstra 98a423b75a prim_import(): prefetch substitute info in parallel using queryMissing() 2012-07-09 09:59:34 -04:00
Eelco Dolstra 1aba0bf0fa nix-store -r: do substitutions in parallel
I.e. when multiple non-derivation arguments are passed to ‘nix-store
-r’ to be substituted, do them in parallel.
2012-06-27 16:58:15 -04:00
Eelco Dolstra 00c98a6bef Use Bison 2.5 2012-04-13 14:28:26 +02:00
Eelco Dolstra 605b16cd7b Fix compilation on FreeBSD
http://hydra.nixos.org/build/2213576

Not sure why compilation doesn't fail on other platforms...
2012-03-05 22:04:40 +01:00
Eelco Dolstra e9fc91df45 Fix error message
This fixes the error message

  error: file `' was not found in the Nix search path (add it using $NIX_PATH or -I)
2012-02-09 18:56:48 +01:00
Eelco Dolstra f491ae97d4 * Inline some functions and get rid of the indirection through
EvalState::eval().  This gives a 12% speedup on ‘nix-instantiate
  /etc/nixos/nixos/ -A system --readonly-mode’ (from 1.01s to 0.89s).
2012-02-04 13:50:25 +00:00
Eelco Dolstra 2bda12ef3b * Print elapsed evaluation time. 2012-02-04 13:27:11 +00:00
Eelco Dolstra baa0501cc1 * Fix importing a derivation. This gave a segfault. 2012-01-26 13:13:00 +00:00
Eelco Dolstra 330df4b4db * Allow comparisons between derivations by comparing the outPath
attributes.
2012-01-19 23:08:47 +00:00
Eelco Dolstra 18047d4625 * Add some debug output to print the derivation name once it's known.
This makes it easier to pinpoint the source of a crash.
2012-01-19 23:07:42 +00:00
Eelco Dolstra 9fe24c5a0d * Don't create thunks for simple constants (integers, strings, paths)
and allocate them only once.
* Move Value and related functions into value.hh.
2012-01-07 17:26:33 +00:00
Eelco Dolstra b52966e821 * Remove dead code. 2012-01-04 21:47:48 +00:00
Eelco Dolstra 35f2a6ba82 * Don't use dynamic_cast, it's very slow. "nix-instantiate
/etc/nixos/nixos -A system" spent about 10% of its time in
  dynamic_cast.
2012-01-04 21:24:11 +00:00
Eelco Dolstra 71f3c46cf6 * Drop the inefficient "Path" suffix in output attribute names. 2012-01-03 15:27:18 +00:00
Eelco Dolstra 921111d197 * Move the implementation of the ‘derivation’ primop into a separate
file.
2012-01-03 14:01:47 +00:00
Eelco Dolstra 5679041132 * The ‘foo.drvPath’ feature was already broken in read-only mode.
Since it's rarely used and fixing it is too much work right now,
  just document it.
2011-12-21 18:19:05 +00:00
Eelco Dolstra b19a0f63db * Simplify the context handling logic. 2011-12-21 15:33:30 +00:00
Eelco Dolstra 194d21f9f6 * Sync with the trunk. 2011-12-16 23:33:01 +00:00
Eelco Dolstra 49f59dceca * Move parseHash16or32 into libutil, and use in nix-hash. 2011-12-02 11:47:06 +00:00
Eelco Dolstra b12b21825c * Allow '<nixexpr>' syntax to be used in nix-instantiate, nix-build
and nix-env, e.g.,

  $ nix-env -f '<nixpkgs>' -i patchelf

  or

  $ nix-build '<nixos/tests>' -A login.test
2011-12-01 16:41:43 +00:00
Shea Levy 3c3107da86 There's no need to mess with drvPath at all 2011-11-06 07:18:19 +00:00
Shea Levy 2ab29be70c Fix faulty reversion of my changes to unsafeDiscardOutputDependency 2011-11-06 07:03:14 +00:00
Shea Levy ca0d47a70c Respect all outputs passed to the derivation, not just the last one 2011-11-06 06:54:05 +00:00
Shea Levy 24b65937e1 Remove the unused sCurrentOutput symbol 2011-11-06 06:28:34 +00:00
Shea Levy 3522730316 Embed output name into the context of the *OutPath attributes and extract it for input derivations
Multiple outputs test passes!
2011-11-06 06:28:30 +00:00
Shea Levy af2e53fd48 Include all outputs of derivations in the closure of explicitly-passed derivation paths
This required adding a queryOutputDerivationNames function in the store API
2011-11-06 06:28:20 +00:00
Shea Levy 981edeab7b The 'insert output between = signs' approach was not helpful 2011-11-06 06:28:14 +00:00
Shea Levy 2721e9f56f Merge from trunk 2011-11-06 00:13:09 +00:00
Eelco Dolstra a12095d3be * In printValueAsXML, handle the case where a "type" attribute is not
a string.  This happens in the NixOS option system.
* Remove a bogus comparison of a unsigned integer with -1.
2011-10-27 19:06:23 +00:00
Shea Levy e81c09edbf Remove the current output metadata from the string for unsaveDiscardOutputDependency 2011-09-16 11:31:00 +00:00
Shea Levy bf50d6ad32 Add information about which output is active to drvPath's context
This will break things that depend on being able to just strip away an equals sign, so those have to be updated next
2011-09-16 11:30:52 +00:00
Shea Levy ffa038f66d Add an sCurrentOutput member to EvalState 2011-09-16 11:30:44 +00:00
Shea Levy f3e410d4bf Add a currentOutput attribute to derivations keep track of which output is active 2011-09-16 11:30:03 +00:00
Shea Levy c172d16b00 First attempt at the output-as-derivation semantics
For each output, this adds a corresponding attribute to the derivation that is
the same as the derivation except for outPath, which is set to the path specific
to that output. Additionally, an "all" attribute is added that is a list of all
of the output derivations. This has to be done outside of derivationStrict as
each output is itself a derivation that contains itself (and all other outputs)
as an attribute. The derivation itself is equivalent to the first output in the
outputs list (or "out" if that list isn't set).
2011-09-14 05:59:17 +00:00
Eelco Dolstra 93227ff65c * Eliminate all uses of the global variable ‘store’ from libstore.
This should also fix:

    nix-instantiate: ./../boost/shared_ptr.hpp:254: T* boost::shared_ptr<T>::operator->() const [with T = nix::StoreAPI]: Assertion `px != 0' failed.

  which was caused by hashDerivationModulo() calling the ‘store’
  object (during store upgrades) before openStore() assigned it.
2011-08-31 21:11:50 +00:00
Eelco Dolstra 2d663b502d * Cache the result of file evaluation (i.e, memoize evalFile()). This
prevents files from being evaluated and stored as values multiple
  times.  For instance, evaluation of the ‘system’ attribute in NixOS
  causes ‘nixpkgs/pkgs/lib/lists.nix’ to be evaluated 2019 times.

  Caching gives a modest speedup and a decent memory footprint
  reduction (e.g., from 1.44s to 1.28s, and from 81 MiB to 59 MiB with
  GC_INITIAL_HEAP_SIZE=100000 on my system).
2011-08-06 19:45:43 +00:00
Eelco Dolstra 9d091ee99a * Handle the case where the search path element is a regular file. 2011-08-06 18:45:28 +00:00
Eelco Dolstra 00a724ebc6 * Remove a debug statement. 2011-08-06 18:24:43 +00:00
Eelco Dolstra 07340b8be7 * Add the Nix corepkgs to the end of the search path. This makes it
possible for other Nix expressions to use corepkgs (mostly useful
  for the buildenv function).
2011-08-06 18:23:38 +00:00
Eelco Dolstra c7101dac0b * Allow redirections in search path entries. E.g. if you have a
directory

    /home/eelco/src/stdenv-updates

  that you want to use as the directory for import such as

    with (import <nixpkgs> { });

  then you can say

    $ nix-build -I nixpkgs=/home/eelco/src/stdenv-updates
2011-08-06 17:48:57 +00:00
Eelco Dolstra 1ecc97b6bd * Add a Nix expression search path feature. Paths between angle
brackets, e.g.

    import <nixpkgs/pkgs/lib>

  are resolved by looking them up relative to the elements listed in
  the search path.  This allows us to get rid of hacks like

    import "${builtins.getEnv "NIXPKGS_ALL"}/pkgs/lib"

  The search path can be specified through the ‘-I’ command-line flag
  and through the colon-separated ‘NIX_PATH’ environment variable,
  e.g.,

    $ nix-build -I /etc/nixos ...

  If a file is not found in the search path, an error message is
  lazily thrown.
2011-08-06 16:05:24 +00:00
Eelco Dolstra 54945a2950 * Refactoring: move parseExprFromFile() and parseExprFromString() into
the EvalState class.
2011-08-06 13:02:55 +00:00
Eelco Dolstra c8606664ab * Don't allow derivations with fixed and non-fixed outputs. 2011-07-20 18:26:00 +00:00
Eelco Dolstra b2027f70d9 * Fix a huuuuge security hole in the Nix daemon. It didn't check that
derivations added to the store by clients have "correct" output
  paths (meaning that the output paths are computed by hashing the
  derivation according to a certain algorithm).  This means that a
  malicious user could craft a special .drv file to build *any*
  desired path in the store with any desired contents (so long as the
  path doesn't already exist).  Then the attacker just needs to wait
  for a victim to come along and install the compromised path.

  For instance, if Alice (the attacker) knows that the latest Firefox
  derivation in Nixpkgs produces the path

    /nix/store/1a5nyfd4ajxbyy97r1fslhgrv70gj8a7-firefox-5.0.1

  then (provided this path doesn't already exist) she can craft a .drv
  file that creates that path (i.e., has it as one of its outputs),
  add it to the store using "nix-store --add", and build it with
  "nix-store -r".  So the fake .drv could write a Trojan to the
  Firefox path.  Then, if user Bob (the victim) comes along and does

    $ nix-env -i firefox
    $ firefox

  he executes the Trojan injected by Alice.

  The fix is to have the Nix daemon verify that derivation outputs are
  correct (in addValidPath()).  This required some refactoring to move
  the hash computation code to libstore.
2011-07-20 18:10:47 +00:00
Eelco Dolstra d329c3ea9d * Support multiple outputs. A derivation can declare multiple outputs
by setting the ‘outputs’ attribute.  For example:

    stdenv.mkDerivation {
      name = "aterm-2.5";

      src = ...;

      outputs = [ "out" "tools" "dev" ];

      configureFlags = "--bindir=$(tools)/bin --includedir=$(dev)/include";
    }

  This derivation creates three outputs, named like this:

    /nix/store/gcnqgllbh01p3d448q8q6pzn2nc2gpyl-aterm-2.5
    /nix/store/gjf1sgirwfnrlr0bdxyrwzpw2r304j02-aterm-2.5-tools
    /nix/store/hp6108bqfgxvza25nnxfs7kj88xi2vdx-aterm-2.5-dev

  That is, the symbolic name of the output is suffixed to the store
  path (except for the ‘out’ output).  Each path is passed to the
  builder through the corresponding environment variable, e.g.,
  ${tools}.

  The main reason for multiple outputs is to allow parts of a package
  to be distributed and garbage-collected separately.  For instance,
  most packages depend on Glibc for its libraries, but don't need its
  header files.  If these are separated into different store paths,
  then a package that depends on the Glibc libraries only causes the
  libraries and not the headers to be downloaded.

  The main problem with multiple outputs is that if one output exists
  while the others have been garbage-collected (or never downloaded in
  the first place), and we want to rebuild the other outputs, then
  this isn't possible because we can't clobber a valid output (it
  might be in active use).  This currently gives an error message
  like:

    error: derivation `/nix/store/1s9zw4c8qydpjyrayxamx2z7zzp5pcgh-aterm-2.5.drv' is blocked by its output paths

  There are two solutions: 1) Do the build in a chroot.  Then we don't
  need to overwrite the existing path.  2) Use hash rewriting (see the
  ASE-2005 paper).  Scary but it should work.

  This is not finished yet.  There is not yet an easy way to refer to
  non-default outputs in Nix expressions.  Also, mutually recursive
  outputs aren't detected yet and cause the garbage collector to
  crash.
2011-07-18 23:31:03 +00:00
Eelco Dolstra d5d4dcd4c9 * Allow attribute names to be strings. Based on the
allow-arbitrary-strinsg-in-names patch by Marc Weber.
2011-07-13 15:53:24 +00:00
Eelco Dolstra 0a623a10c7 * Allow a default value in attribute selection by writing
x.y.z or default

  (as originally proposed in
  https://mail.cs.uu.nl/pipermail/nix-dev/2009-September/002989.html).

  For instance, an expression like

    stdenv.lib.attrByPath ["features" "ckSched"] false args

  can now be written as

    args.features.ckSched or false
2011-07-13 12:19:57 +00:00
Eelco Dolstra 2b9e29b1c8 * Change the right-hand side of the ‘.’ operator from an attribute to
an attribute path.  This is a refactoring to support default values.
2011-07-06 12:28:57 +00:00
Eelco Dolstra 5637037802 * In the ‘?’ operator, allow attribute paths. For instance, you can
write ‘attrs ? a.b’ to test whether ‘attrs’ has an attribute ‘a’
  containing an attribute ‘b’.  This is more convenient than ‘attrs ?
  a && attrs.a ? b’.

  Slight change in the semantics: it's no longer an error if the
  left-hand side of ‘?’ is not an attribute set.  In that case it just
  returns false.  So, ‘null ? foo’ no longer throws an error.
2011-07-06 10:58:17 +00:00
Eelco Dolstra 538b7caab0 * Don't allocate a big initial GC address space on machines with
little RAM.  Even if the memory isn't actually used, it can cause
  problems with the overcommit heuristics in the kernel.  So use a VM
  space of 25% of RAM, up to 384 MB.
2011-02-10 14:31:04 +00:00
Eelco Dolstra 5a6b039802 * Don't call GC_expand_hp unless we're actually using the garbage
collector.
2011-02-09 22:59:50 +00:00
Ludovic Courtès f1462c208b Use $BDW_GC_LIBS instead of a custom variable. 2011-02-09 21:23:13 +00:00
Eelco Dolstra 9db190eb31 * builtins.substring: if "start" is beyond the end of the string,
return the empty string.
2011-01-14 12:47:10 +00:00
Eelco Dolstra 812fae424e * DrvInfo contains pointers to expressions, so DrvInfos should be
traced by the garbage collector.  Otherwise "nix-env -u" can crash
  randomly.
2010-11-25 13:47:34 +00:00
Eelco Dolstra 0c4828ea05 * new(UseGC) is inexplicably slower than GC_MALLOC, so prefer the
latter.
2010-10-28 12:50:01 +00:00
Eelco Dolstra e11e6fb1c6 * Handle out of memory condition. 2010-10-28 12:29:40 +00:00
Eelco Dolstra 43535499f3 * When allocating an attribute set, reserve enough space for all
elements.  This prevents the vector from having to resize itself.
2010-10-24 20:09:37 +00:00
Eelco Dolstra e0b7fb8f27 * Keep attribute sets in sorted order to speed up attribute lookups.
* Simplify the representation of attributes in the AST.
* Change the behaviour of listToAttrs() in case of duplicate names.
2010-10-24 19:52:33 +00:00
Eelco Dolstra 2dc6d50941 * Don't create thunks for variable lookups (if possible). This
significantly reduces the number of values allocated (e.g. from 8.7m
  to 4.9m for the Bittorrent test).
2010-10-24 14:20:02 +00:00
Eelco Dolstra 0b305c534f * Store attribute sets as a vector instead of a map (i.e. a red-black
tree).  This saves a lot of memory.  The vector should be sorted so
  that names can be looked up using binary search, but this is not the
  case yet.  (Surprisingly, looking up attributes using linear search
  doesn't have a big impact on performance.)

  Memory consumption for

    $ nix-instantiate /etc/nixos/nixos/tests -A bittorrent.test --readonly-mode

  on x86_64-linux with GC enabled is now 185 MiB (compared to 946
  MiB on the trunk).
2010-10-24 00:41:29 +00:00