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
|
#include "attr-path.hh"
#include "eval-inline.hh"
#include "util.hh"
namespace nix {
static Strings parseAttrPath(std::string_view s)
{
Strings res;
string cur;
auto i = s.begin();
while (i != s.end()) {
if (*i == '.') {
res.push_back(cur);
cur.clear();
} else if (*i == '"') {
++i;
while (1) {
if (i == s.end())
throw ParseError("missing closing quote in selection path '%1%'", s);
if (*i == '"') break;
cur.push_back(*i++);
}
} else
cur.push_back(*i);
++i;
}
if (!cur.empty()) res.push_back(cur);
return res;
}
std::vector<Symbol> parseAttrPath(EvalState & state, std::string_view s)
{
std::vector<Symbol> res;
for (auto & a : parseAttrPath(s))
res.push_back(state.symbols.create(a));
return res;
}
std::pair<Value *, Pos> findAlongAttrPath(EvalState & state, const string & attrPath,
Bindings & autoArgs, Value & vIn)
{
Strings tokens = parseAttrPath(attrPath);
Value * v = &vIn;
Pos pos = noPos;
for (auto & attr : tokens) {
/* Is i an index (integer) or a normal attribute name? */
auto attrIndex = string2Int<unsigned int>(attr);
/* Evaluate the expression. */
Value * vNew = state.allocValue();
state.autoCallFunction(autoArgs, *v, *vNew);
v = vNew;
state.forceValue(*v);
/* It should evaluate to either a set or an expression,
according to what is specified in the attrPath. */
if (!attrIndex) {
if (v->type() != nAttrs)
throw TypeError(
"the expression selected by the selection path '%1%' should be a set but is %2%",
attrPath,
showType(*v));
if (attr.empty())
throw Error("empty attribute name in selection path '%1%'", attrPath);
Bindings::iterator a = v->attrs->find(state.symbols.create(attr));
if (a == v->attrs->end())
throw AttrPathNotFound("attribute '%1%' in selection path '%2%' not found", attr, attrPath);
v = &*a->value;
pos = *a->pos;
}
else {
if (!v->isList())
throw TypeError(
"the expression selected by the selection path '%1%' should be a list but is %2%",
attrPath,
showType(*v));
if (*attrIndex >= v->listSize())
throw AttrPathNotFound("list index %1% in selection path '%2%' is out of range", *attrIndex, attrPath);
v = v->listElems()[*attrIndex];
pos = noPos;
}
}
return {v, pos};
}
Pos findDerivationFilename(EvalState & state, Value & v, std::string what)
{
Value * v2;
try {
auto dummyArgs = state.allocBindings(0);
v2 = findAlongAttrPath(state, "meta.position", *dummyArgs, v).first;
} catch (Error &) {
throw NoPositionInfo("package '%s' has no source location information", what);
}
// FIXME: is it possible to extract the Pos object instead of doing this
// toString + parsing?
auto pos = state.forceString(*v2);
auto colon = pos.rfind(':');
if (colon == std::string::npos)
throw ParseError("cannot parse meta.position attribute '%s'", pos);
std::string filename(pos, 0, colon);
unsigned int lineno;
try {
lineno = std::stoi(std::string(pos, colon + 1));
} catch (std::invalid_argument & e) {
throw ParseError("cannot parse line number '%s'", pos);
}
Symbol file = state.symbols.create(filename);
return { foFile, file, lineno, 0 };
}
}
|
