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Merge pull request #11682 from NaN-git/opt-str

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Remove superfluous `std::string` copy operations
This commit is contained in:
Robert Hensing 2024-10-12 10:59:40 +02:00 • committed by GitHub
commit 30c4f5eb51
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GPG key ID: B5690EEEBB952194
16 changed files with 72 additions and 54 deletions
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17
src/libexpr/eval.cc
View file

@ -539,7 +539,7 @@ std::optional<EvalState::Doc> EvalState::getDoc(Value & v)
if (v.isLambda()) {
auto exprLambda = v.payload.lambda.fun;
std::stringstream s(std::ios_base::out);
std::ostringstream s;
std::string name;
auto pos = positions[exprLambda->getPos()];
std::string docStr;
@ -571,17 +571,12 @@ std::optional<EvalState::Doc> EvalState::getDoc(Value & v)
s << docStr;
s << '\0'; // for making a c string below
std::string ss = s.str();
return Doc {
.pos = pos,
.name = name,
.arity = 0, // FIXME: figure out how deep by syntax only? It's not semantically useful though...
.args = {},
.doc =
// FIXME: this leaks; make the field std::string?
strdup(ss.data()),
.doc = makeImmutableString(toView(s)), // NOTE: memory leak when compiled without GC
};
}
if (isFunctor(v)) {
@ -1805,11 +1800,9 @@ void ExprIf::eval(EvalState & state, Env & env, Value & v)
void ExprAssert::eval(EvalState & state, Env & env, Value & v)
{
if (!state.evalBool(env, cond, pos, "in the condition of the assert statement")) {
auto exprStr = ({
std::ostringstream out;
cond->show(state.symbols, out);
out.str();
});
std::ostringstream out;
cond->show(state.symbols, out);
auto exprStr = toView(out);
if (auto eq = dynamic_cast<ExprOpEq *>(cond)) {
try {

9
src/libexpr/get-drvs.cc
View file

@ -374,11 +374,12 @@ static void getDerivations(EvalState & state, Value & vIn,
bound to the attribute with the "lower" name should take
precedence). */
for (auto & i : v.attrs()->lexicographicOrder(state.symbols)) {
std::string_view symbol{state.symbols[i->name]};
try {
debug("evaluating attribute '%1%'", state.symbols[i->name]);
if (!std::regex_match(std::string(state.symbols[i->name]), attrRegex))
debug("evaluating attribute '%1%'", symbol);
if (!std::regex_match(symbol.begin(), symbol.end(), attrRegex))
continue;
std::string pathPrefix2 = addToPath(pathPrefix, state.symbols[i->name]);
std::string pathPrefix2 = addToPath(pathPrefix, symbol);
if (combineChannels)
getDerivations(state, *i->value, pathPrefix2, autoArgs, drvs, done, ignoreAssertionFailures);
else if (getDerivation(state, *i->value, pathPrefix2, drvs, done, ignoreAssertionFailures)) {
@ -392,7 +393,7 @@ static void getDerivations(EvalState & state, Value & vIn,
}
}
} catch (Error & e) {
e.addTrace(state.positions[i->pos], "while evaluating the attribute '%s'", state.symbols[i->name]);
e.addTrace(state.positions[i->pos], "while evaluating the attribute '%s'", symbol);
throw;
}
}

19
src/libexpr/primops.cc
View file

@ -40,6 +40,13 @@ namespace nix {
* Miscellaneous
*************************************************************/
static inline Value * mkString(EvalState & state, const std::csub_match & match)
{
Value * v = state.allocValue();
v->mkString({match.first, match.second});
return v;
}
StringMap EvalState::realiseContext(const NixStringContext & context, StorePathSet * maybePathsOut, bool isIFD)
{
std::vector<DerivedPath::Built> drvs;
@ -2129,7 +2136,7 @@ static void prim_toXML(EvalState & state, const PosIdx pos, Value * * args, Valu
std::ostringstream out;
NixStringContext context;
printValueAsXML(state, true, false, *args[0], out, context, pos);
v.mkString(out.str(), context);
v.mkString(toView(out), context);
}
static RegisterPrimOp primop_toXML({
@ -2237,7 +2244,7 @@ static void prim_toJSON(EvalState & state, const PosIdx pos, Value * * args, Val
std::ostringstream out;
NixStringContext context;
printValueAsJSON(state, true, *args[0], pos, out, context);
v.mkString(out.str(), context);
v.mkString(toView(out), context);
}
static RegisterPrimOp primop_toJSON({
@ -4268,7 +4275,7 @@ void prim_match(EvalState & state, const PosIdx pos, Value * * args, Value & v)
if (!match[i + 1].matched)
v2 = &state.vNull;
else
(v2 = state.allocValue())->mkString(match[i + 1].str());
v2 = mkString(state, match[i + 1]);
v.mkList(list);
} catch (std::regex_error & e) {
@ -4352,7 +4359,7 @@ void prim_split(EvalState & state, const PosIdx pos, Value * * args, Value & v)
auto match = *i;
// Add a string for non-matched characters.
(list[idx++] = state.allocValue())->mkString(match.prefix().str());
list[idx++] = mkString(state, match.prefix());
// Add a list for matched substrings.
const size_t slen = match.size() - 1;
@ -4363,14 +4370,14 @@ void prim_split(EvalState & state, const PosIdx pos, Value * * args, Value & v)
if (!match[si + 1].matched)
v2 = &state.vNull;
else
(v2 = state.allocValue())->mkString(match[si + 1].str());
v2 = mkString(state, match[si + 1]);
}
(list[idx++] = state.allocValue())->mkList(list2);
// Add a string for non-matched suffix characters.
if (idx == 2 * len)
(list[idx++] = state.allocValue())->mkString(match.suffix().str());
list[idx++] = mkString(state, match.suffix());
}
assert(idx == 2 * len + 1);

2
src/libexpr/primops/fromTOML.cc
View file

@ -66,7 +66,7 @@ static void prim_fromTOML(EvalState & state, const PosIdx pos, Value * * args, V
attrs.alloc("_type").mkString("timestamp");
std::ostringstream s;
s << t;
attrs.alloc("value").mkString(s.str());
attrs.alloc("value").mkString(toView(s));
v.mkAttrs(attrs);
} else {
throw std::runtime_error("Dates and times are not supported");

2
src/libexpr/print.cc
View file

@ -460,7 +460,7 @@ private:
std::ostringstream s;
s << state.positions[v.payload.lambda.fun->pos];
output << " @ " << filterANSIEscapes(s.str());
output << " @ " << filterANSIEscapes(toView(s));
}
} else if (v.isPrimOp()) {
if (v.primOp())