about summary refs log tree commit diff
path: root/src/libexpr/eval.hh
blob: ed572b4291a1acd4a9052214ff5344abe7958cae (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
#pragma once

#include "value.hh"
#include "nixexpr.hh"
#include "symbol-table.hh"
#include "hash.hh"

#include <map>

#if HAVE_BOEHMGC
#include <gc/gc_allocator.h>
#endif


namespace nix {


class EvalState;


struct Attr
{
    Symbol name;
    Value * value;
    Pos * pos;
    Attr(Symbol name, Value * value, Pos * pos = &noPos)
        : name(name), value(value), pos(pos) { };
    Attr() : pos(&noPos) { };
    bool operator < (const Attr & a) const
    {
        return name < a.name;
    }
};


class Bindings
{
public:
    typedef uint32_t size_t;

private:
    size_t size_, capacity;
    Attr attrs[0];

    Bindings(uint32_t capacity) : size_(0), capacity(capacity) { }

public:
    size_t size() { return size_; }

    bool empty() { return !size_; }

    typedef Attr * iterator;

    void push_back(const Attr & attr)
    {
        assert(size_ < capacity);
        attrs[size_++] = attr;
    }

    iterator find(const Symbol & name)
    {
        Attr key(name, 0);
        iterator i = std::lower_bound(begin(), end(), key);
        if (i != end() && i->name == name) return i;
        return end();
    }

    iterator begin() { return &attrs[0]; }
    iterator end() { return &attrs[size_]; }

    Attr & operator[](size_t pos)
    {
        return attrs[pos];
    }

    void sort();

    friend class EvalState;
};


typedef void (* PrimOpFun) (EvalState & state, const Pos & pos, Value * * args, Value & v);


struct PrimOp
{
    PrimOpFun fun;
    unsigned int arity;
    Symbol name;
    PrimOp(PrimOpFun fun, unsigned int arity, Symbol name)
        : fun(fun), arity(arity), name(name) { }
};


struct Env
{
    Env * up;
    unsigned short size; // used by ‘valueSize’
    unsigned short prevWith:15; // nr of levels up to next `with' environment
    unsigned short haveWithAttrs:1;
    Value * values[0];
};


void mkString(Value & v, const string & s, const PathSet & context = PathSet());

void copyContext(const Value & v, PathSet & context);


/* Cache for calls to addToStore(); maps source paths to the store
   paths. */
typedef std::map<Path, Path> SrcToStore;


std::ostream & operator << (std::ostream & str, const Value & v);


typedef list<std::pair<string, Path> > SearchPath;


class EvalState
{
public:
    SymbolTable symbols;

    const Symbol sWith, sOutPath, sDrvPath, sType, sMeta, sName, sValue,
        sSystem, sOverrides, sOutputs, sOutputName, sIgnoreNulls,
        sFile, sLine, sColumn;
    Symbol sDerivationNix;

    /* If set, force copying files to the Nix store even if they
       already exist there. */
    bool repair;

private:
    SrcToStore srcToStore;

    /* A cache from path names to values. */
#if HAVE_BOEHMGC
    typedef std::map<Path, Value, std::less<Path>, traceable_allocator<std::pair<const Path, Value> > > FileEvalCache;
#else
    typedef std::map<Path, Value> FileEvalCache;
#endif
    FileEvalCache fileEvalCache;

    SearchPath searchPath;

public:

    EvalState(const Strings & _searchPath);
    ~EvalState();

    void addToSearchPath(const string & s, bool warn = false);

    /* Parse a Nix expression from the specified file. */
    Expr * parseExprFromFile(const Path & path);
    Expr * parseExprFromFile(const Path & path, StaticEnv & staticEnv);

    /* Parse a Nix expression from the specified string. */
    Expr * parseExprFromString(const string & s, const Path & basePath, StaticEnv & staticEnv);
    Expr * parseExprFromString(const string & s, const Path & basePath);

    /* Evaluate an expression read from the given file to normal
       form. */
    void evalFile(const Path & path, Value & v);

    void resetFileCache();

    /* Look up a file in the search path. */
    Path findFile(const string & path);
    Path findFile(SearchPath & searchPath, const string & path);

    /* Evaluate an expression to normal form, storing the result in
       value `v'. */
    void eval(Expr * e, Value & v);

    /* Evaluation the expression, then verify that it has the expected
       type. */
    inline bool evalBool(Env & env, Expr * e);
    inline bool evalBool(Env & env, Expr * e, const Pos & pos);
    inline void evalAttrs(Env & env, Expr * e, Value & v);

    /* If `v' is a thunk, enter it and overwrite `v' with the result
       of the evaluation of the thunk.  If `v' is a delayed function
       application, call the function and overwrite `v' with the
       result.  Otherwise, this is a no-op. */
    inline void forceValue(Value & v);

    /* Force a value, then recursively force list elements and
       attributes. */
    void forceValueDeep(Value & v);

    /* Force `v', and then verify that it has the expected type. */
    NixInt forceInt(Value & v, const Pos & pos);
    bool forceBool(Value & v);
    inline void forceAttrs(Value & v);
    inline void forceAttrs(Value & v, const Pos & pos);
    inline void forceList(Value & v);
    inline void forceList(Value & v, const Pos & pos);
    void forceFunction(Value & v, const Pos & pos); // either lambda or primop
    string forceString(Value & v, const Pos & pos = noPos);
    string forceString(Value & v, PathSet & context);
    string forceStringNoCtx(Value & v, const Pos & pos = noPos);

    /* Return true iff the value `v' denotes a derivation (i.e. a
       set with attribute `type = "derivation"'). */
    bool isDerivation(Value & v);

    /* String coercion.  Converts strings, paths and derivations to a
       string.  If `coerceMore' is set, also converts nulls, integers,
       booleans and lists to a string.  If `copyToStore' is set,
       referenced paths are copied to the Nix store as a side effect. */
    string coerceToString(const Pos & pos, Value & v, PathSet & context,
        bool coerceMore = false, bool copyToStore = true);

    string copyPathToStore(PathSet & context, const Path & path);

    /* Path coercion.  Converts strings, paths and derivations to a
       path.  The result is guaranteed to be a canonicalised, absolute
       path.  Nothing is copied to the store. */
    Path coerceToPath(const Pos & pos, Value & v, PathSet & context);

public:

    /* The base environment, containing the builtin functions and
       values. */
    Env & baseEnv;

    /* The same, but used during parsing to resolve variables. */
    StaticEnv staticBaseEnv; // !!! should be private

private:

    unsigned int baseEnvDispl;

    void createBaseEnv();

    void addConstant(const string & name, Value & v);

    void addPrimOp(const string & name,
        unsigned int arity, PrimOpFun primOp);

public:

    void getBuiltin(const string & name, Value & v);

private:

    inline Value * lookupVar(Env * env, const ExprVar & var, bool noEval);

    friend struct ExprVar;
    friend struct ExprAttrs;
    friend struct ExprLet;

    Expr * parse(const char * text, const Path & path,
        const Path & basePath, StaticEnv & staticEnv);

public:

    /* Do a deep equality test between two values.  That is, list
       elements and attributes are compared recursively. */
    bool eqValues(Value & v1, Value & v2);

    void callFunction(Value & fun, Value & arg, Value & v, const Pos & pos);
    void callPrimOp(Value & fun, Value & arg, Value & v, const Pos & pos);

    /* Automatically call a function for which each argument has a
       default value or has a binding in the `args' map. */
    void autoCallFunction(Bindings & args, Value & fun, Value & res);

    /* Allocation primitives. */
    Value * allocValue();
    Env & allocEnv(unsigned int size);

    Value * allocAttr(Value & vAttrs, const Symbol & name);

    Bindings * allocBindings(Bindings::size_t capacity);

    void mkList(Value & v, unsigned int length);
    void mkAttrs(Value & v, unsigned int expected);
    void mkThunk_(Value & v, Expr * expr);
    void mkPos(Value & v, Pos * pos);

    void concatLists(Value & v, unsigned int nrLists, Value * * lists, const Pos & pos);

    /* Print statistics. */
    void printStats();

    void printCanaries();

private:

    unsigned long nrEnvs;
    unsigned long nrValuesInEnvs;
    unsigned long nrValues;
    unsigned long nrListElems;
    unsigned long nrAttrsets;
    unsigned long nrAttrsInAttrsets;
    unsigned long nrOpUpdates;
    unsigned long nrOpUpdateValuesCopied;
    unsigned long nrListConcats;
    unsigned long nrPrimOpCalls;
    unsigned long nrFunctionCalls;

    bool countCalls;

    typedef std::map<Symbol, unsigned int> PrimOpCalls;
    PrimOpCalls primOpCalls;

    typedef std::map<ExprLambda *, unsigned int> FunctionCalls;
    FunctionCalls functionCalls;

    void incrFunctionCall(ExprLambda * fun);

    typedef std::map<Pos, unsigned int> AttrSelects;
    AttrSelects attrSelects;

    friend struct ExprOpUpdate;
    friend struct ExprOpConcatLists;
    friend struct ExprSelect;
    friend void prim_getAttr(EvalState & state, const Pos & pos, Value * * args, Value & v);

#if HAVE_BOEHMGC
    std::set<Value *> gcCanaries;
    friend void canaryFinalizer(GC_PTR obj, GC_PTR client_data);
    friend void prim_gcCanary(EvalState & state, const Pos & pos, Value * * args, Value & v);
#endif
};


/* Return a string representing the type of the value `v'. */
string showType(const Value & v);


/* If `path' refers to a directory, then append "/default.nix". */
Path resolveExprPath(Path path);


}