lix/src/libexpr/get-drvs.cc
Eelco Dolstra fe2d869e04 * Store user environment manifests as a Nix expression in
$out/manifest.nix rather than as an ATerm.

  (Hm, I thought I committed this two days ago...)
2010-04-21 15:08:58 +00:00

211 lines
6.5 KiB
C++

#include "get-drvs.hh"
#include "util.hh"
namespace nix {
string DrvInfo::queryDrvPath(EvalState & state) const
{
if (drvPath == "" && attrs) {
Bindings::iterator i = attrs->find(state.sDrvPath);
PathSet context;
(string &) drvPath = i != attrs->end() ? state.coerceToPath(i->second, context) : "";
}
return drvPath;
}
string DrvInfo::queryOutPath(EvalState & state) const
{
if (outPath == "" && attrs) {
Bindings::iterator i = attrs->find(state.sOutPath);
PathSet context;
(string &) outPath = i != attrs->end() ? state.coerceToPath(i->second, context) : "";
}
return outPath;
}
MetaInfo DrvInfo::queryMetaInfo(EvalState & state) const
{
if (metaInfoRead) return meta;
(bool &) metaInfoRead = true;
Bindings::iterator a = attrs->find(state.sMeta);
if (a == attrs->end()) return meta; /* fine, empty meta information */
state.forceAttrs(a->second);
foreach (Bindings::iterator, i, *a->second.attrs) {
MetaValue value;
state.forceValue(i->second);
if (i->second.type == tString) {
value.type = MetaValue::tpString;
value.stringValue = i->second.string.s;
} else if (i->second.type == tInt) {
value.type = MetaValue::tpInt;
value.intValue = i->second.integer;
} else if (i->second.type == tList) {
value.type = MetaValue::tpStrings;
for (unsigned int j = 0; j < i->second.list.length; ++j)
value.stringValues.push_back(state.forceStringNoCtx(*i->second.list.elems[j]));
} else continue;
((MetaInfo &) meta)[i->first] = value;
}
return meta;
}
MetaValue DrvInfo::queryMetaInfo(EvalState & state, const string & name) const
{
/* !!! evaluates all meta attributes => inefficient */
return queryMetaInfo(state)[name];
}
void DrvInfo::setMetaInfo(const MetaInfo & meta)
{
metaInfoRead = true;
this->meta = meta;
}
/* Cache for already considered attrsets. */
typedef set<Bindings *> Done;
/* Evaluate value `v'. 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
`v'. */
static bool getDerivation(EvalState & state, Value & v,
const string & attrPath, DrvInfos & drvs, Done & done)
{
try {
state.forceValue(v);
if (!state.isDerivation(v)) return true;
/* Remove spurious duplicates (e.g., an attribute set like
`rec { x = derivation {...}; y = x;}'. */
if (done.find(v.attrs) != done.end()) return false;
done.insert(v.attrs);
DrvInfo drv;
Bindings::iterator i = v.attrs->find(state.sName);
/* !!! We really would like to have a decent back trace here. */
if (i == v.attrs->end()) throw TypeError("derivation name missing");
drv.name = state.forceStringNoCtx(i->second);
i = v.attrs->find(state.sSystem);
if (i == v.attrs->end())
drv.system = "unknown";
else
drv.system = state.forceStringNoCtx(i->second);
drv.attrs = v.attrs;
drv.attrPath = attrPath;
drvs.push_back(drv);
return false;
} catch (AssertionError & e) {
return false;
}
}
bool getDerivation(EvalState & state, Value & v, DrvInfo & drv)
{
Done done;
DrvInfos drvs;
getDerivation(state, v, "", drvs, done);
if (drvs.size() != 1) return false;
drv = drvs.front();
return true;
}
static string addToPath(const string & s1, const string & s2)
{
return s1.empty() ? s2 : s1 + "." + s2;
}
static void getDerivations(EvalState & state, Value & vIn,
const string & pathPrefix, const Bindings & autoArgs,
DrvInfos & drvs, Done & done)
{
Value v;
state.autoCallFunction(autoArgs, vIn, v);
/* Process the expression. */
DrvInfo drv;
if (!getDerivation(state, v, pathPrefix, drvs, done)) ;
else if (v.type == tAttrs) {
/* !!! undocumented hackery to support combining channels in
nix-env.cc. */
bool combineChannels = v.attrs->find(state.symbols.create("_combineChannels")) != v.attrs->end();
/* Consider the attributes in sorted order to get more
deterministic behaviour in nix-env operations (e.g. when
there are names clashes between derivations, the derivation
bound to the attribute with the "lower" name should take
precedence). */
typedef std::map<string, Symbol> SortedSymbols;
SortedSymbols attrs;
foreach (Bindings::iterator, i, *v.attrs)
attrs.insert(std::pair<string, Symbol>(i->first, i->first));
foreach (SortedSymbols::iterator, i, attrs) {
startNest(nest, lvlDebug, format("evaluating attribute `%1%'") % i->first);
string pathPrefix2 = addToPath(pathPrefix, i->first);
Value & v2((*v.attrs)[i->second]);
if (combineChannels)
getDerivations(state, v2, pathPrefix2, autoArgs, drvs, done);
else if (getDerivation(state, v2, pathPrefix2, drvs, done)) {
/* If the value of this attribute is itself an
attribute set, should we recurse into it? => Only
if it has a `recurseForDerivations = true'
attribute. */
if (v2.type == tAttrs) {
Bindings::iterator j = v2.attrs->find(state.symbols.create("recurseForDerivations"));
if (j != v2.attrs->end() && state.forceBool(j->second))
getDerivations(state, v2, pathPrefix2, autoArgs, drvs, done);
}
}
}
}
else if (v.type == tList) {
for (unsigned int n = 0; n < v.list.length; ++n) {
startNest(nest, lvlDebug,
format("evaluating list element"));
string pathPrefix2 = addToPath(pathPrefix, (format("%1%") % n).str());
if (getDerivation(state, *v.list.elems[n], pathPrefix2, drvs, done))
getDerivations(state, *v.list.elems[n], pathPrefix2, autoArgs, drvs, done);
}
}
else throw TypeError("expression does not evaluate to a derivation (or a set or list of those)");
}
void getDerivations(EvalState & state, Value & v, const string & pathPrefix,
const Bindings & autoArgs, DrvInfos & drvs)
{
Done done;
getDerivations(state, v, pathPrefix, autoArgs, drvs, done);
}
}