lix/src/libexpr/value-to-xml.cc
pennae 8775be3393 store Symbols in a table as well, like positions
this slightly increases the amount of memory used for any given symbol, but this
increase is more than made up for if the symbol is referenced more than once in
the EvalState that holds it. on average every symbol should be referenced at
least twice (once to introduce a binding, once to use it), so we expect no
increase in memory on average.

symbol tables are limited to 2³² entries like position tables, and similar
arguments apply to why overflow is not likely: 2³² symbols would require as many
string instances (at 24 bytes each) and map entries (at 24 bytes or more each,
assuming that the map holds on average at most one item per bucket as the docs
say). a full symbol table would require at least 192GB of memory just for
symbols, which is well out of reach. (an ofborg eval of nixpks today creates
less than a million symbols!)
2022-04-21 21:56:31 +02:00

186 lines
5.6 KiB
C++

#include "value-to-xml.hh"
#include "xml-writer.hh"
#include "eval-inline.hh"
#include "util.hh"
#include <cstdlib>
namespace nix {
static XMLAttrs singletonAttrs(const std::string & name, const std::string & value)
{
XMLAttrs attrs;
attrs[name] = value;
return attrs;
}
static void printValueAsXML(EvalState & state, bool strict, bool location,
Value & v, XMLWriter & doc, PathSet & context, PathSet & drvsSeen,
const PosIdx pos);
static void posToXML(EvalState & state, XMLAttrs & xmlAttrs, const Pos & pos)
{
xmlAttrs["path"] = pos.file;
xmlAttrs["line"] = (format("%1%") % pos.line).str();
xmlAttrs["column"] = (format("%1%") % pos.column).str();
}
static void showAttrs(EvalState & state, bool strict, bool location,
Bindings & attrs, XMLWriter & doc, PathSet & context, PathSet & drvsSeen)
{
StringSet names;
for (auto & i : attrs)
names.emplace(state.symbols[i.name]);
for (auto & i : names) {
Attr & a(*attrs.find(state.symbols.create(i)));
XMLAttrs xmlAttrs;
xmlAttrs["name"] = i;
if (location && a.pos) posToXML(state, xmlAttrs, state.positions[a.pos]);
XMLOpenElement _(doc, "attr", xmlAttrs);
printValueAsXML(state, strict, location,
*a.value, doc, context, drvsSeen, a.pos);
}
}
static void printValueAsXML(EvalState & state, bool strict, bool location,
Value & v, XMLWriter & doc, PathSet & context, PathSet & drvsSeen,
const PosIdx pos)
{
checkInterrupt();
if (strict) state.forceValue(v, pos);
switch (v.type()) {
case nInt:
doc.writeEmptyElement("int", singletonAttrs("value", (format("%1%") % v.integer).str()));
break;
case nBool:
doc.writeEmptyElement("bool", singletonAttrs("value", v.boolean ? "true" : "false"));
break;
case nString:
/* !!! show the context? */
copyContext(v, context);
doc.writeEmptyElement("string", singletonAttrs("value", v.string.s));
break;
case nPath:
doc.writeEmptyElement("path", singletonAttrs("value", v.path));
break;
case nNull:
doc.writeEmptyElement("null");
break;
case nAttrs:
if (state.isDerivation(v)) {
XMLAttrs xmlAttrs;
Bindings::iterator a = v.attrs->find(state.symbols.create("derivation"));
Path drvPath;
a = v.attrs->find(state.sDrvPath);
if (a != v.attrs->end()) {
if (strict) state.forceValue(*a->value, a->pos);
if (a->value->type() == nString)
xmlAttrs["drvPath"] = drvPath = a->value->string.s;
}
a = v.attrs->find(state.sOutPath);
if (a != v.attrs->end()) {
if (strict) state.forceValue(*a->value, a->pos);
if (a->value->type() == nString)
xmlAttrs["outPath"] = a->value->string.s;
}
XMLOpenElement _(doc, "derivation", xmlAttrs);
if (drvPath != "" && drvsSeen.insert(drvPath).second)
showAttrs(state, strict, location, *v.attrs, doc, context, drvsSeen);
else
doc.writeEmptyElement("repeated");
}
else {
XMLOpenElement _(doc, "attrs");
showAttrs(state, strict, location, *v.attrs, doc, context, drvsSeen);
}
break;
case nList: {
XMLOpenElement _(doc, "list");
for (auto v2 : v.listItems())
printValueAsXML(state, strict, location, *v2, doc, context, drvsSeen, pos);
break;
}
case nFunction: {
if (!v.isLambda()) {
// FIXME: Serialize primops and primopapps
doc.writeEmptyElement("unevaluated");
break;
}
XMLAttrs xmlAttrs;
if (location) posToXML(state, xmlAttrs, state.positions[v.lambda.fun->pos]);
XMLOpenElement _(doc, "function", xmlAttrs);
if (v.lambda.fun->hasFormals()) {
XMLAttrs attrs;
if (v.lambda.fun->arg) attrs["name"] = state.symbols[v.lambda.fun->arg];
if (v.lambda.fun->formals->ellipsis) attrs["ellipsis"] = "1";
XMLOpenElement _(doc, "attrspat", attrs);
for (auto & i : v.lambda.fun->formals->lexicographicOrder(state.symbols))
doc.writeEmptyElement("attr", singletonAttrs("name", state.symbols[i.name]));
} else
doc.writeEmptyElement("varpat", singletonAttrs("name", state.symbols[v.lambda.fun->arg]));
break;
}
case nExternal:
v.external->printValueAsXML(state, strict, location, doc, context, drvsSeen, pos);
break;
case nFloat:
doc.writeEmptyElement("float", singletonAttrs("value", (format("%1%") % v.fpoint).str()));
break;
case nThunk:
doc.writeEmptyElement("unevaluated");
}
}
void ExternalValueBase::printValueAsXML(EvalState & state, bool strict,
bool location, XMLWriter & doc, PathSet & context, PathSet & drvsSeen,
const PosIdx pos) const
{
doc.writeEmptyElement("unevaluated");
}
void printValueAsXML(EvalState & state, bool strict, bool location,
Value & v, std::ostream & out, PathSet & context, const PosIdx pos)
{
XMLWriter doc(true, out);
XMLOpenElement root(doc, "expr");
PathSet drvsSeen;
printValueAsXML(state, strict, location, v, doc, context, drvsSeen, pos);
}
}