aboutsummaryrefslogtreecommitdiff
path: root/src/nix/make-content-addressable.cc
blob: c506eabd89ac8426ca6c93689404b8c68d4623a1 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
#include "command.hh"
#include "store-api.hh"
#include "references.hh"
#include "common-args.hh"
#include "json.hh"

using namespace nix;

struct CmdMakeContentAddressable : StorePathsCommand, MixJSON
{
    CmdMakeContentAddressable()
    {
        realiseMode = Build;
    }

    std::string description() override
    {
        return "rewrite a path or closure to content-addressable form";
    }

    Examples examples() override
    {
        return {
            Example{
                "To create a content-addressable representation of GNU Hello (but not its dependencies):",
                "nix make-content-addressable nixpkgs.hello"
            },
            Example{
                "To compute a content-addressable representation of the current NixOS system closure:",
                "nix make-content-addressable -r /run/current-system"
            },
        };
    }

    Category category() override { return catUtility; }

    void run(ref<Store> store, StorePaths storePaths) override
    {
        auto paths = store->topoSortPaths(StorePathSet(storePaths.begin(), storePaths.end()));

        std::reverse(paths.begin(), paths.end());

        std::map<StorePath, StorePath> remappings;

        auto jsonRoot = json ? std::make_unique<JSONObject>(std::cout) : nullptr;
        auto jsonRewrites = json ? std::make_unique<JSONObject>(jsonRoot->object("rewrites")) : nullptr;

        for (auto & path : paths) {
            auto pathS = store->printStorePath(path);
            auto oldInfo = store->queryPathInfo(path);
            std::string oldHashPart(path.hashPart());

            StringSink sink;
            store->narFromPath(path, sink);

            StringMap rewrites;

            StorePathSet references;
            bool hasSelfReference = false;
            for (auto & ref : oldInfo->references) {
                if (ref == path)
                    hasSelfReference = true;
                else {
                    auto i = remappings.find(ref);
                    auto replacement = i != remappings.end() ? i->second : ref;
                    // FIXME: warn about unremapped paths?
                    if (replacement != ref)
                        rewrites.insert_or_assign(store->printStorePath(ref), store->printStorePath(replacement));
                    references.insert(std::move(replacement));
                }
            }

            *sink.s = rewriteStrings(*sink.s, rewrites);

            HashModuloSink hashModuloSink(htSHA256, oldHashPart);
            hashModuloSink((unsigned char *) sink.s->data(), sink.s->size());

            auto narHash = hashModuloSink.finish().first;

            ValidPathInfo info(store->makeFixedOutputPath(FileIngestionMethod::Recursive, narHash, path.name(), references, hasSelfReference));
            info.references = std::move(references);
            if (hasSelfReference) info.references.insert(info.path);
            info.narHash = narHash;
            info.narSize = sink.s->size();
            info.ca = FixedOutputHash {
                FileIngestionMethod::Recursive,
                info.narHash,
            };

            if (!json)
                printInfo("rewrote '%s' to '%s'", pathS, store->printStorePath(info.path));

            auto source = sinkToSource([&](Sink & nextSink) {
                RewritingSink rsink2(oldHashPart, std::string(info.path.hashPart()), nextSink);
                rsink2((unsigned char *) sink.s->data(), sink.s->size());
                rsink2.flush();
            });

            store->addToStore(info, *source);

            if (json)
                jsonRewrites->attr(store->printStorePath(path), store->printStorePath(info.path));

            remappings.insert_or_assign(std::move(path), std::move(info.path));
        }
    }
};

static auto r1 = registerCommand<CmdMakeContentAddressable>("make-content-addressable");