aboutsummaryrefslogtreecommitdiff
path: root/nix/libstore/derivations.cc
blob: d91e42784ca56b7dd732ad051cfcd61ed2e5b391 (about) (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
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
#include "derivations.hh"
#include "store-api.hh"
#include "globals.hh"
#include "util.hh"
#include "misc.hh"


namespace nix {


void DerivationOutput::parseHashInfo(bool & recursive, HashType & hashType, Hash & hash) const
{
    recursive = false;
    string algo = hashAlgo;

    if (string(algo, 0, 2) == "r:") {
        recursive = true;
        algo = string(algo, 2);
    }

    hashType = parseHashType(algo);
    if (hashType == htUnknown)
        throw Error(format("unknown hash algorithm `%1%'") % algo);

    hash = parseHash(hashType, this->hash);
}


Path writeDerivation(StoreAPI & store,
    const Derivation & drv, const string & name, bool repair)
{
    PathSet references;
    references.insert(drv.inputSrcs.begin(), drv.inputSrcs.end());
    foreach (DerivationInputs::const_iterator, i, drv.inputDrvs)
        references.insert(i->first);
    /* Note that the outputs of a derivation are *not* references
       (that can be missing (of course) and should not necessarily be
       held during a garbage collection). */
    string suffix = name + drvExtension;
    string contents = unparseDerivation(drv);
    return settings.readOnlyMode
        ? computeStorePathForText(suffix, contents, references)
        : store.addTextToStore(suffix, contents, references, repair);
}


static Path parsePath(std::istream & str)
{
    string s = parseString(str);
    if (s.size() == 0 || s[0] != '/')
        throw Error(format("bad path `%1%' in derivation") % s);
    return s;
}


static StringSet parseStrings(std::istream & str, bool arePaths)
{
    StringSet res;
    while (!endOfList(str))
        res.insert(arePaths ? parsePath(str) : parseString(str));
    return res;
}


Derivation parseDerivation(const string & s)
{
    Derivation drv;
    std::istringstream str(s);
    expect(str, "Derive([");

    /* Parse the list of outputs. */
    while (!endOfList(str)) {
        DerivationOutput out;
        expect(str, "("); string id = parseString(str);
        expect(str, ","); out.path = parsePath(str);
        expect(str, ","); out.hashAlgo = parseString(str);
        expect(str, ","); out.hash = parseString(str);
        expect(str, ")");
        drv.outputs[id] = out;
    }

    /* Parse the list of input derivations. */
    expect(str, ",[");
    while (!endOfList(str)) {
        expect(str, "(");
        Path drvPath = parsePath(str);
        expect(str, ",[");
        drv.inputDrvs[drvPath] = parseStrings(str, false);
        expect(str, ")");
    }

    expect(str, ",["); drv.inputSrcs = parseStrings(str, true);
    expect(str, ","); drv.platform = parseString(str);
    expect(str, ","); drv.builder = parseString(str);

    /* Parse the builder arguments. */
    expect(str, ",[");
    while (!endOfList(str))
        drv.args.push_back(parseString(str));

    /* Parse the environment variables. */
    expect(str, ",[");
    while (!endOfList(str)) {
        expect(str, "("); string name = parseString(str);
        expect(str, ","); string value = parseString(str);
        expect(str, ")");
        drv.env[name] = value;
    }

    expect(str, ")");
    return drv;
}


static void printString(string & res, const string & s)
{
    res += '"';
    for (const char * i = s.c_str(); *i; i++)
        if (*i == '\"' || *i == '\\') { res += "\\"; res += *i; }
        else if (*i == '\n') res += "\\n";
        else if (*i == '\r') res += "\\r";
        else if (*i == '\t') res += "\\t";
        else res += *i;
    res += '"';
}


template<class ForwardIterator>
static void printStrings(string & res, ForwardIterator i, ForwardIterator j)
{
    res += '[';
    bool first = true;
    for ( ; i != j; ++i) {
        if (first) first = false; else res += ',';
        printString(res, *i);
    }
    res += ']';
}


string unparseDerivation(const Derivation & drv)
{
    string s;
    s.reserve(65536);
    s += "Derive([";

    bool first = true;
    foreach (DerivationOutputs::const_iterator, i, drv.outputs) {
        if (first) first = false; else s += ',';
        s += '('; printString(s, i->first);
        s += ','; printString(s, i->second.path);
        s += ','; printString(s, i->second.hashAlgo);
        s += ','; printString(s, i->second.hash);
        s += ')';
    }

    s += "],[";
    first = true;
    foreach (DerivationInputs::const_iterator, i, drv.inputDrvs) {
        if (first) first = false; else s += ',';
        s += '('; printString(s, i->first);
        s += ','; printStrings(s, i->second.begin(), i->second.end());
        s += ')';
    }

    s += "],";
    printStrings(s, drv.inputSrcs.begin(), drv.inputSrcs.end());

    s += ','; printString(s, drv.platform);
    s += ','; printString(s, drv.builder);
    s += ','; printStrings(s, drv.args.begin(), drv.args.end());

    s += ",[";
    first = true;
    foreach (StringPairs::const_iterator, i, drv.env) {
        if (first) first = false; else s += ',';
        s += '('; printString(s, i->first);
        s += ','; printString(s, i->second);
        s += ')';
    }

    s += "])";

    return s;
}


bool isDerivation(const string & fileName)
{
    return hasSuffix(fileName, drvExtension);
}


bool isFixedOutputDrv(const Derivation & drv)
{
    return drv.outputs.size() == 1 &&
        drv.outputs.begin()->first == "out" &&
        drv.outputs.begin()->second.hash != "";
}


DrvHashes drvHashes;


/* Returns the hash of a derivation modulo fixed-output
   subderivations.  A fixed-output derivation is a derivation with one
   output (`out') for which an expected hash and hash algorithm are
   specified (using the `outputHash' and `outputHashAlgo'
   attributes).  We don't want changes to such derivations to
   propagate upwards through the dependency graph, changing output
   paths everywhere.

   For instance, if we change the url in a call to the `fetchurl'
   function, we do not want to rebuild everything depending on it
   (after all, (the hash of) the file being downloaded is unchanged).
   So the *output paths* should not change.  On the other hand, the
   *derivation paths* should change to reflect the new dependency
   graph.

   That's what this function does: it returns a hash which is just the
   hash of the derivation ATerm, except that any input derivation
   paths have been replaced by the result of a recursive call to this
   function, and that for fixed-output derivations we return a hash of
   its output path. */
Hash hashDerivationModulo(StoreAPI & store, Derivation drv)
{
    /* Return a fixed hash for fixed-output derivations. */
    if (isFixedOutputDrv(drv)) {
        DerivationOutputs::const_iterator i = drv.outputs.begin();
        return hashString(htSHA256, "fixed:out:"
            + i->second.hashAlgo + ":"
            + i->second.hash + ":"
            + i->second.path);
    }

    /* For other derivations, replace the inputs paths with recursive
       calls to this function.*/
    DerivationInputs inputs2;
    foreach (DerivationInputs::const_iterator, i, drv.inputDrvs) {
        Hash h = drvHashes[i->first];
        if (h.type == htUnknown) {
            assert(store.isValidPath(i->first));
            Derivation drv2 = parseDerivation(readFile(i->first));
            h = hashDerivationModulo(store, drv2);
            drvHashes[i->first] = h;
        }
        inputs2[printHash(h)] = i->second;
    }
    drv.inputDrvs = inputs2;

    return hashString(htSHA256, unparseDerivation(drv));
}


DrvPathWithOutputs parseDrvPathWithOutputs(const string & s)
{
    size_t n = s.find("!");
    return n == s.npos
        ? DrvPathWithOutputs(s, std::set<string>())
        : DrvPathWithOutputs(string(s, 0, n), tokenizeString<std::set<string> >(string(s, n + 1), ","));
}


Path makeDrvPathWithOutputs(const Path & drvPath, const std::set<string> & outputs)
{
    return outputs.empty()
        ? drvPath
        : drvPath + "!" + concatStringsSep(",", outputs);
}


bool wantOutput(const string & output, const std::set<string> & wanted)
{
    return wanted.empty() || wanted.find(output) != wanted.end();
}


}