#include "misc.hh"
#include "store-api.hh"
#include "local-store.hh"
#include "globals.hh"


namespace nix {


Derivation derivationFromPath(StoreAPI & store, const Path & drvPath)
{
    assertStorePath(drvPath);
    store.ensurePath(drvPath);
    return readDerivation(drvPath);
}


void computeFSClosure(StoreAPI & store, const Path & path,
    PathSet & paths, bool flipDirection, bool includeOutputs, bool includeDerivers)
{
    if (paths.find(path) != paths.end()) return;
    paths.insert(path);

    PathSet edges;

    if (flipDirection) {
        store.queryReferrers(path, edges);

        if (includeOutputs) {
            PathSet derivers = store.queryValidDerivers(path);
            foreach (PathSet::iterator, i, derivers)
                edges.insert(*i);
        }

        if (includeDerivers && isDerivation(path)) {
            PathSet outputs = store.queryDerivationOutputs(path);
            foreach (PathSet::iterator, i, outputs)
                if (store.isValidPath(*i) && store.queryDeriver(*i) == path)
                    edges.insert(*i);
        }

    } else {
        store.queryReferences(path, edges);

        if (includeOutputs && isDerivation(path)) {
            PathSet outputs = store.queryDerivationOutputs(path);
            foreach (PathSet::iterator, i, outputs)
                if (store.isValidPath(*i)) edges.insert(*i);
        }

        if (includeDerivers) {
            Path deriver = store.queryDeriver(path);
            if (store.isValidPath(deriver)) edges.insert(deriver);
        }
    }

    foreach (PathSet::iterator, i, edges)
        computeFSClosure(store, *i, paths, flipDirection, includeOutputs, includeDerivers);
}


static void dfsVisit(StoreAPI & store, const PathSet & paths,
    const Path & path, PathSet & visited, Paths & sorted,
    PathSet & parents)
{
    if (parents.find(path) != parents.end())
        throw BuildError(format("cycle detected in the references of `%1%'") % path);

    if (visited.find(path) != visited.end()) return;
    visited.insert(path);
    parents.insert(path);

    PathSet references;
    if (store.isValidPath(path))
        store.queryReferences(path, references);

    foreach (PathSet::iterator, i, references)
        /* Don't traverse into paths that don't exist.  That can
           happen due to substitutes for non-existent paths. */
        if (*i != path && paths.find(*i) != paths.end())
            dfsVisit(store, paths, *i, visited, sorted, parents);

    sorted.push_front(path);
    parents.erase(path);
}


Paths topoSortPaths(StoreAPI & store, const PathSet & paths)
{
    Paths sorted;
    PathSet visited, parents;
    foreach (PathSet::const_iterator, i, paths)
        dfsVisit(store, paths, *i, visited, sorted, parents);
    return sorted;
}


}
lass='msg-avail'>...<span class='msg-tooltip'>This code duplicates the (gnu system image) and (gnu build image) code. Using
VM for image generation is not needed, not portable and really slow. Remove
all the VM image generation code to make sure that only the image API is used.

* gnu/build/vm.scm: Remove it. Move the qemu-command procedure to ...
* gnu/build/marionette.scm: ... here.
* gnu/local.mk (GNU_SYSTEM_MODULES): Adapt it.
* tests/modules.scm: Ditto.
* gnu/tests/install.scm: Ditto.
* gnu/system/vm.scm: Adapt it and remove expression-&gt;derivation-in-linux-vm,
qemu-img, system-qemu-image/shared-store and system-docker-image procedures.
* doc/guix.texi (G-Expressions): Adapt it.
</span></span></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2017-05-25 14:25:17 +0200'>2017-05-25</span></td><td><a href='/guix/commit/tests/modules.scm?id=bfe5264aa10c1af64adc5c24d0cf091562e3e09c'>modules: Raise an error when a dependency could not be found.</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/modules.scm (&amp;missing-dependency-error): New error condition.
(source-module-dependencies): Raise it when 'search-path' returns #f.
* tests/modules.scm ("&amp;missing-dependency-error"): New test.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2016-09-05 00:06:47 +0200'>2016-09-05</span></td><td><a href='/guix/commit/tests/modules.scm?id=7ca87354db53fd1e1a7a3dfeddb9a598ea064bbe'>Add (guix modules).</a><span class='msg-avail'>...<span class='msg-tooltip'>* guix/modules.scm, tests/modules.scm: New files.
* Makefile.am (MODULES, SCM_TESTS): Add them.
* doc/guix.texi (G-Expressions): Add an example of
'source-module-closure'.
</span></span></td><td>Ludovic Courtès</td></tr>