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
|
#pragma once
#include "symbol-table.hh"
namespace nix {
typedef enum {
tInt = 1,
tBool,
tString,
tPath,
tNull,
tAttrs,
tList,
tThunk,
tApp,
tLambda,
tBlackhole,
tPrimOp,
tPrimOpApp,
tExternal,
} ValueType;
class Bindings;
struct Env;
struct Expr;
struct ExprLambda;
struct PrimOp;
struct PrimOp;
class Symbol;
struct Pos;
class EvalState;
class XMLWriter;
typedef long NixInt;
/* External values must descend from ExternalValueBase, so that
* type-agnostic nix functions (e.g. showType) can be implemented
*/
class ExternalValueBase
{
friend std::ostream & operator << (std::ostream & str, const ExternalValueBase & v);
protected:
/* Print out the value */
virtual std::ostream & print(std::ostream & str) const = 0;
public:
/* Return a simple string describing the type */
virtual string showType() const = 0;
/* Return a string to be used in builtins.typeOf */
virtual string typeOf() const = 0;
/* How much space does this value take up */
virtual size_t valueSize(std::set<const void *> & seen) const = 0;
/* Coerce the value to a string. Defaults to uncoercable, i.e. throws an
* error
*/
virtual string coerceToString(const Pos & pos, PathSet & context, bool copyMore, bool copyToStore) const;
/* Compare to another value of the same type. Defaults to uncomparable,
* i.e. always false.
*/
virtual bool operator==(const ExternalValueBase & b) const;
/* Print the value as JSON. Defaults to unconvertable, i.e. throws an error */
virtual void printValueAsJSON(EvalState & state, bool strict,
std::ostream & str, PathSet & context) const;
/* Print the value as XML. Defaults to unevaluated */
virtual void printValueAsXML(EvalState & state, bool strict, bool location,
XMLWriter & doc, PathSet & context, PathSet & drvsSeen) const;
virtual ~ExternalValueBase()
{
};
};
std::ostream & operator << (std::ostream & str, const ExternalValueBase & v);
struct Value
{
ValueType type;
union
{
NixInt integer;
bool boolean;
/* Strings in the evaluator carry a so-called `context' which
is a list of strings representing store paths. This is to
allow users to write things like
"--with-freetype2-library=" + freetype + "/lib"
where `freetype' is a derivation (or a source to be copied
to the store). If we just concatenated the strings without
keeping track of the referenced store paths, then if the
string is used as a derivation attribute, the derivation
will not have the correct dependencies in its inputDrvs and
inputSrcs.
The semantics of the context is as follows: when a string
with context C is used as a derivation attribute, then the
derivations in C will be added to the inputDrvs of the
derivation, and the other store paths in C will be added to
the inputSrcs of the derivations.
For canonicity, the store paths should be in sorted order. */
struct {
const char * s;
const char * * context; // must be in sorted order
} string;
const char * path;
Bindings * attrs;
struct {
unsigned int length;
Value * * elems;
} list;
struct {
Env * env;
Expr * expr;
} thunk;
struct {
Value * left, * right;
} app;
struct {
Env * env;
ExprLambda * fun;
} lambda;
PrimOp * primOp;
struct {
Value * left, * right;
} primOpApp;
ExternalValueBase * external;
};
};
/* After overwriting an app node, be sure to clear pointers in the
Value to ensure that the target isn't kept alive unnecessarily. */
static inline void clearValue(Value & v)
{
v.app.left = v.app.right = 0;
}
static inline void mkInt(Value & v, NixInt n)
{
clearValue(v);
v.type = tInt;
v.integer = n;
}
static inline void mkBool(Value & v, bool b)
{
clearValue(v);
v.type = tBool;
v.boolean = b;
}
static inline void mkNull(Value & v)
{
clearValue(v);
v.type = tNull;
}
static inline void mkApp(Value & v, Value & left, Value & right)
{
v.type = tApp;
v.app.left = &left;
v.app.right = &right;
}
static inline void mkStringNoCopy(Value & v, const char * s)
{
v.type = tString;
v.string.s = s;
v.string.context = 0;
}
static inline void mkString(Value & v, const Symbol & s)
{
mkStringNoCopy(v, ((const string &) s).c_str());
}
void mkString(Value & v, const char * s);
static inline void mkPathNoCopy(Value & v, const char * s)
{
clearValue(v);
v.type = tPath;
v.path = s;
}
void mkPath(Value & v, const char * s);
/* Compute the size in bytes of the given value, including all values
and environments reachable from it. Static expressions (Exprs) are
not included. */
size_t valueSize(Value & v);
}
|
