about summary refs log tree commit diff
path: root/src/libexpr/primops.cc
blob: 6588922c26b9657e6aa65b18deef7aa5293ce7e2 (plain) (blame)
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
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
#include "normalise.hh"
#include "eval.hh"
#include "globals.hh"


/* Load and evaluate an expression from path specified by the
   argument. */ 
static Expr primImport(EvalState & state, const ATermVector & args)
{
    ATMatcher m;
    string path;
    if (!(atMatch(m, args[0]) >> "Path" >> path))
        throw Error("path expected");
    return evalFile(state, path);
}


static PathSet storeExprRootsCached(EvalState & state, const Path & nePath)
{
    DrvPaths::iterator i = state.drvPaths.find(nePath);
    if (i != state.drvPaths.end())
        return i->second;
    else {
        PathSet paths = storeExprRoots(nePath);
        state.drvPaths[nePath] = paths;
        return paths;
    }
}


static Hash hashDerivation(EvalState & state, StoreExpr ne)
{
    if (ne.type == StoreExpr::neDerivation) {
	PathSet inputs2;
        for (PathSet::iterator i = ne.derivation.inputs.begin();
             i != ne.derivation.inputs.end(); i++)
        {
            DrvHashes::iterator j = state.drvHashes.find(*i);
            if (j == state.drvHashes.end())
                throw Error(format("don't know expression `%1%'") % (string) *i);
            inputs2.insert(j->second);
        }
	ne.derivation.inputs = inputs2;
    }
    return hashTerm(unparseStoreExpr(ne));
}


static Path copyAtom(EvalState & state, const Path & srcPath)
{
    /* !!! should be cached */
    Path dstPath(addToStore(srcPath));

    ClosureElem elem;
    StoreExpr ne;
    ne.type = StoreExpr::neClosure;
    ne.closure.roots.insert(dstPath);
    ne.closure.elems[dstPath] = elem;

    Hash drvHash = hashDerivation(state, ne);
    Path drvPath = writeTerm(unparseStoreExpr(ne), "");
    state.drvHashes[drvPath] = drvHash;

    printMsg(lvlChatty, format("copied `%1%' -> closure `%2%'")
        % srcPath % drvPath);
    return drvPath;
}


static string addInput(EvalState & state, 
    Path & nePath, StoreExpr & ne)
{
    PathSet paths = storeExprRootsCached(state, nePath);
    if (paths.size() != 1) abort();
    Path path = *(paths.begin());
    ne.derivation.inputs.insert(nePath);
    return path;
}


static void processBinding(EvalState & state, Expr e, StoreExpr & ne,
    Strings & ss)
{
    e = evalExpr(state, e);

    ATMatcher m;
    string s;
    ATermList es;
    int n;
    Expr e1, e2;

    if (atMatch(m, e) >> "Str" >> s) ss.push_back(s);
    else if (atMatch(m, e) >> "Uri" >> s) ss.push_back(s);
    else if (atMatch(m, e) >> "Bool" >> "True") ss.push_back("1");
    else if (atMatch(m, e) >> "Bool" >> "False") ss.push_back("");

    else if (atMatch(m, e) >> "Int" >> n) {
        ostringstream st;
        st << n;
        ss.push_back(st.str());
    }

    else if (atMatch(m, e) >> "Attrs") {
        Expr a = queryAttr(e, "type");
        if (a && evalString(state, a) == "derivation") {
            a = queryAttr(e, "drvPath");
            if (!a) throw Error("derivation name missing");
            Path drvPath = evalPath(state, a);

            a = queryAttr(e, "drvHash");
            if (!a) throw Error("derivation hash missing");
            Hash drvHash = parseHash(evalString(state, a));

            state.drvHashes[drvPath] = drvHash;
            
            ss.push_back(addInput(state, drvPath, ne));
        } else
            throw Error("invalid derivation attribute");
    }

    else if (atMatch(m, e) >> "Path" >> s) {
        Path drvPath = copyAtom(state, s);
        ss.push_back(addInput(state, drvPath, ne));
    }
    
    else if (atMatch(m, e) >> "List" >> es) {
        for (ATermIterator i(es); i; ++i) {
            startNest(nest, lvlVomit, format("processing list element"));
	    processBinding(state, evalExpr(state, *i), ne, ss);
        }
    }

    else if (atMatch(m, e) >> "Null") ss.push_back("");

    else if (atMatch(m, e) >> "SubPath" >> e1 >> e2) {
        Strings ss2;
        processBinding(state, evalExpr(state, e1), ne, ss2);
        if (ss2.size() != 1)
            throw Error("left-hand side of `~' operator cannot be a list");
        e2 = evalExpr(state, e2);
        if (!(atMatch(m, e2) >> "Str" >> s ||
             (atMatch(m, e2) >> "Path" >> s)))
            throw Error("right-hand side of `~' operator must be a path or string");
        ss.push_back(canonPath(ss2.front() + "/" + s));
    }
    
    else throw Error("invalid derivation attribute");
}


static string concatStrings(const Strings & ss)
{
    string s;
    bool first = true;
    for (Strings::const_iterator i = ss.begin(); i != ss.end(); ++i) {
        if (!first) s += " "; else first = false;
        s += *i;
    }
    return s;
}


/* Construct (as a unobservable side effect) a Nix derivation
   expression that performs the derivation described by the argument
   set.  Returns the original set extended with the following
   attributes: `outPath' containing the primary output path of the
   derivation; `drvPath' containing the path of the Nix expression;
   and `type' set to `derivation' to indicate that this is a
   derivation. */
static Expr primDerivation(EvalState & state, const ATermVector & _args)
{
    startNest(nest, lvlVomit, "evaluating derivation");

    ATermMap attrs;
    Expr args = _args[0];
    args = evalExpr(state, args);
    queryAllAttrs(args, attrs, true);

    /* Build the derivation expression by processing the attributes. */
    StoreExpr ne;
    ne.type = StoreExpr::neDerivation;

    string drvName;
    Hash outHash;
    bool outHashGiven = false;

    for (ATermIterator i(attrs.keys()); i; ++i) {
        string key = aterm2String(*i);
        ATerm value;
        Expr pos;
        ATerm rhs = attrs.get(key);
        ATMatcher m;
        if (!(atMatch(m, rhs) >> "" >> value >> pos)) abort();
        startNest(nest, lvlVomit, format("processing attribute `%1%'") % key);

        Strings ss;
        try {
            processBinding(state, value, ne, ss);
        } catch (Error & e) {
            throw Error(format("while processing derivation attribute `%1%' at %2%:\n%3%")
                % key % showPos(pos) % e.msg());
        }

        /* The `args' attribute is special: it supplies the
           command-line arguments to the builder. */
        if (key == "args") {
            for (Strings::iterator i = ss.begin(); i != ss.end(); ++i)
                ne.derivation.args.push_back(*i);
        }

        /* All other attributes are passed to the builder through the
           environment. */
        else {
            string s = concatStrings(ss);
            ne.derivation.env[key] = s;
            if (key == "builder") ne.derivation.builder = s;
            else if (key == "system") ne.derivation.platform = s;
            else if (key == "name") drvName = s;
            else if (key == "id") { 
                outHash = parseHash(s);
                outHashGiven = true;
            }
        }
    }
    
    /* Do we have all required attributes? */
    if (ne.derivation.builder == "")
        throw Error("required attribute `builder' missing");
    if (ne.derivation.platform == "")
        throw Error("required attribute `system' missing");
    if (drvName == "")
        throw Error("required attribute `name' missing");

    /* Check the derivation name.  It shouldn't contain whitespace,
       but we are conservative here: we check whether only
       alphanumerics and some other characters appear. */
    string validChars = "+-._?=";
    for (string::iterator i = drvName.begin(); i != drvName.end(); ++i)
        if (!((*i >= 'A' && *i <= 'Z') ||
              (*i >= 'a' && *i <= 'z') ||
              (*i >= '0' && *i <= '9') ||
              validChars.find(*i) != string::npos))
        {
            throw Error(format("invalid character `%1%' in derivation name `%2%'")
                % *i % drvName);
        }
        
    /* Determine the output path by hashing the Nix expression with no
       outputs to produce a unique but deterministic path name for
       this derivation. */
    if (!outHashGiven) outHash = hashDerivation(state, ne);
    Path outPath = canonPath(nixStore + "/" + 
        ((string) outHash).c_str() + "-" + drvName);
    ne.derivation.env["out"] = outPath;
    ne.derivation.outputs.insert(outPath);

    /* Write the resulting term into the Nix store directory. */
    Hash drvHash = outHashGiven
        ? hashString((string) outHash + outPath)
        : hashDerivation(state, ne);
    Path drvPath = writeTerm(unparseStoreExpr(ne), "-d-" + drvName);

    printMsg(lvlChatty, format("instantiated `%1%' -> `%2%'")
        % drvName % drvPath);

    attrs.set("outPath", ATmake("(Path(<str>), NoPos)", outPath.c_str()));
    attrs.set("drvPath", ATmake("(Path(<str>), NoPos)", drvPath.c_str()));
    attrs.set("drvHash", ATmake("(Str(<str>), NoPos)", ((string) drvHash).c_str()));
    attrs.set("type", ATmake("(Str(\"derivation\"), NoPos)"));

    return makeAttrs(attrs);
}


/* Return the base name of the given string, i.e., everything
   following the last slash. */
static Expr primBaseNameOf(EvalState & state, const ATermVector & args)
{
    string s = evalString(state, args[0]);
    return ATmake("Str(<str>)", baseNameOf(s).c_str());
}


/* Convert the argument (which can be a path or a uri) to a string. */
static Expr primToString(EvalState & state, const ATermVector & args)
{
    Expr arg = evalExpr(state, args[0]);
    ATMatcher m;
    string s;
    if (atMatch(m, arg) >> "Str" >> s ||
        atMatch(m, arg) >> "Path" >> s ||
        atMatch(m, arg) >> "Uri" >> s)
        return ATmake("Str(<str>)", s.c_str());
    else throw Error("cannot coerce value to string");
}


/* Boolean constructors. */
static Expr primTrue(EvalState & state, const ATermVector & args)
{
    return ATmake("Bool(True)");
}


static Expr primFalse(EvalState & state, const ATermVector & args)
{
    return ATmake("Bool(False)");
}


/* Return the null value. */
Expr primNull(EvalState & state, const ATermVector & args)
{
    return ATmake("Null");
}


/* Determine whether the argument is the null value. */
Expr primIsNull(EvalState & state, const ATermVector & args)
{
    Expr arg = evalExpr(state, args[0]);
    ATMatcher m;
    return makeBool(atMatch(m, arg) >> "Null");
}


/* Apply a function to every element of a list. */
Expr primMap(EvalState & state, const ATermVector & args)
{
    Expr fun = evalExpr(state, args[0]);
    Expr list = evalExpr(state, args[1]);

    ATMatcher m;

    ATermList list2;
    if (!(atMatch(m, list) >> "List" >> list2))
        throw Error("`map' expects a list as its second argument");

    ATermList list3 = ATempty;
    for (ATermIterator i(list2); i; ++i)
        list3 = ATinsert(list3,
            ATmake("Call(<term>, <term>)", fun, *i));

    return ATmake("List(<term>)", ATreverse(list3));
}


void EvalState::addPrimOps()
{
    addPrimOp("true", 0, primTrue);
    addPrimOp("false", 0, primFalse);
    addPrimOp("null", 0, primNull);

    addPrimOp("import", 1, primImport);
    addPrimOp("derivation", 1, primDerivation);
    addPrimOp("baseNameOf", 1, primBaseNameOf);
    addPrimOp("toString", 1, primToString);
    addPrimOp("isNull", 1, primIsNull);

    addPrimOp("map", 2, primMap);
}