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#include "get-drvs.hh"
#include "nixexpr-ast.hh"
string DrvInfo::queryDrvPath(EvalState & state) const
{
if (drvPath == "") {
Expr a = attrs.get("drvPath");
(string &) drvPath = a ? evalPath(state, a) : "";
}
return drvPath;
}
string DrvInfo::queryOutPath(EvalState & state) const
{
if (outPath == "") {
Expr a = attrs.get("outPath");
if (!a) throw Error("output path missing");
(string &) outPath = evalPath(state, a);
}
return outPath;
}
MetaInfo DrvInfo::queryMetaInfo(EvalState & state) const
{
MetaInfo meta;
Expr a = attrs.get("meta");
if (!a) return meta; /* fine, empty meta information */
ATermMap attrs2;
queryAllAttrs(evalExpr(state, a), attrs2);
for (ATermIterator i(attrs2.keys()); i; ++i) {
ATerm s = coerceToString(evalExpr(state, attrs2.get(*i)));
if (s)
meta[aterm2String(*i)] = aterm2String(s);
/* For future compatibility, ignore attribute values that are
not strings. */
}
return meta;
}
/* Cache for already evaluated derivations. Usually putting ATerms in
a STL container is unsafe (they're not scanning for GC roots), but
here it doesn't matter; everything in this set is reachable from
the stack as well. */
typedef set<Expr> Exprs;
/* Evaluate expression `e'. If it evaluates to an attribute set of
type `derivation', then put information about it in `drvs' (unless
it's already in `doneExprs'). The result boolean indicates whether
it makes sense for the caller to recursively search for derivations
in `e'. */
static bool getDerivation(EvalState & state, Expr e,
DrvInfos & drvs, Exprs & doneExprs)
{
try {
ATermList es;
e = evalExpr(state, e);
if (!matchAttrs(e, es)) return true;
ATermMap attrs;
queryAllAttrs(e, attrs, false);
Expr a = attrs.get("type");
if (!a || evalString(state, a) != "derivation") return true;
/* Remove spurious duplicates (e.g., an attribute set like
`rec { x = derivation {...}; y = x;}'. */
if (doneExprs.find(e) != doneExprs.end()) return false;
doneExprs.insert(e);
DrvInfo drv;
a = attrs.get("name");
if (!a) throw badTerm("derivation name missing", e);
drv.name = evalString(state, a);
a = attrs.get("system");
if (!a)
drv.system = "unknown";
else
drv.system = evalString(state, a);
drv.attrs = attrs;
drvs.push_back(drv);
return false;
} catch (AssertionError & e) {
return false;
}
}
bool getDerivation(EvalState & state, Expr e, DrvInfo & drv)
{
Exprs doneExprs;
DrvInfos drvs;
getDerivation(state, e, drvs, doneExprs);
if (drvs.size() != 1) return false;
drv = drvs.front();
return true;
}
static void getDerivations(EvalState & state, Expr e,
DrvInfos & drvs, Exprs & doneExprs, const string & attrPath)
{
/* Automatically call functions that have defaults for all
arguments. */
ATermList formals;
ATerm body, pos;
if (matchFunction(e, formals, body, pos)) {
for (ATermIterator i(formals); i; ++i) {
Expr name, def;
if (matchNoDefFormal(*i, name))
throw Error(format("expression evaluates to a function with no-default arguments (`%1%')")
% aterm2String(name));
else if (!matchDefFormal(*i, name, def))
abort(); /* can't happen */
}
getDerivations(state,
makeCall(e, makeAttrs(ATermMap())),
drvs, doneExprs, attrPath);
return;
}
/* Parse the start of attrPath. */
enum { apNone, apAttr, apIndex } apType;
string attrPathRest;
string attr;
int attrIndex;
Error attrError =
Error(format("attribute selection path `%1%' does not match expression") % attrPath);
if (attrPath.empty())
apType = apNone;
else {
string::size_type dot = attrPath.find(".");
if (dot == string::npos) {
attrPathRest = "";
attr = attrPath;
} else {
attrPathRest = string(attrPath, dot + 1);
attr = string(attrPath, 0, dot);
}
apType = apAttr;
if (string2Int(attr, attrIndex)) apType = apIndex;
}
/* Process the expression. */
ATermList es;
DrvInfo drv;
if (!getDerivation(state, e, drvs, doneExprs)) {
if (apType != apNone) throw attrError;
return;
}
e = evalExpr(state, e);
if (matchAttrs(e, es)) {
if (apType != apNone && apType != apAttr) throw attrError;
ATermMap drvMap;
queryAllAttrs(e, drvMap);
if (apType == apNone) {
for (ATermIterator i(drvMap.keys()); i; ++i) {
startNest(nest, lvlDebug,
format("evaluating attribute `%1%'") % aterm2String(*i));
if (getDerivation(state, drvMap.get(*i), drvs, doneExprs)) {
/* If the value of this attribute is itself an
attribute set, should we recurse into it?
=> Only if it has a `recurseForDerivations = true'
attribute. */
ATermList es;
Expr e = evalExpr(state, drvMap.get(*i));
if (matchAttrs(e, es)) {
ATermMap attrs;
queryAllAttrs(e, attrs, false);
if (attrs.get("recurseForDerivations") &&
evalBool(state, attrs.get("recurseForDerivations")))
getDerivations(state, e, drvs, doneExprs, attrPathRest);
}
}
}
} else {
Expr e2 = drvMap.get(attr);
if (!e2) throw Error(format("attribute `%1%' in selection path not found") % attr);
startNest(nest, lvlDebug,
format("evaluating attribute `%1%'") % attr);
getDerivation(state, e2, drvs, doneExprs);
if (!attrPath.empty())
getDerivations(state, e2, drvs, doneExprs, attrPathRest);
}
return;
}
if (matchList(e, es)) {
if (apType != apNone && apType != apIndex) throw attrError;
if (apType == apNone) {
for (ATermIterator i(es); i; ++i) {
startNest(nest, lvlDebug,
format("evaluating list element"));
if (getDerivation(state, *i, drvs, doneExprs))
getDerivations(state, *i, drvs, doneExprs, attrPathRest);
}
} else {
Expr e2 = ATelementAt(es, attrIndex);
if (!e2) throw Error(format("list index %1% in selection path not found") % attrIndex);
startNest(nest, lvlDebug,
format("evaluating list element"));
if (getDerivation(state, e2, drvs, doneExprs))
getDerivations(state, e2, drvs, doneExprs, attrPathRest);
}
return;
}
throw Error("expression does not evaluate to a derivation (or a set or list of those)");
}
void getDerivations(EvalState & state, Expr e, DrvInfos & drvs,
const string & attrPath)
{
Exprs doneExprs;
getDerivations(state, e, drvs, doneExprs, attrPath);
}
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