diff options
| -rw-r--r-- | third_party/nix/src/libexpr/attr-set.cc | 13 |
1 files changed, 11 insertions, 2 deletions
diff --git a/third_party/nix/src/libexpr/attr-set.cc b/third_party/nix/src/libexpr/attr-set.cc index c1b86387be..d44df990ad 100644 --- a/third_party/nix/src/libexpr/attr-set.cc +++ b/third_party/nix/src/libexpr/attr-set.cc @@ -10,6 +10,8 @@ namespace nix { +static Bindings ZERO_BINDINGS; + // This function inherits its name from previous implementations, in // which Bindings was backed by an array of elements which was scanned // linearly. @@ -21,6 +23,8 @@ namespace nix { // This behaviour is mimicked by using .insert(), which will *not* // override existing values. void Bindings::push_back(const Attr& attr) { + assert(this != &ZERO_BINDINGS); + auto [_, inserted] = attributes_.insert({attr.name, attr}); if (!inserted) { @@ -53,19 +57,24 @@ Bindings::iterator Bindings::begin() { return attributes_.begin(); } Bindings::iterator Bindings::end() { return attributes_.end(); } void Bindings::merge(const Bindings& other) { + assert(this != &ZERO_BINDINGS); for (auto& [key, value] : other.attributes_) { this->attributes_.insert_or_assign(key, value); } } -Bindings* Bindings::NewGC(size_t _capacity) { +Bindings* Bindings::NewGC(size_t capacity) { + if (capacity == 0) { + return &ZERO_BINDINGS; + } + return new (GC) Bindings; } void EvalState::mkAttrs(Value& v, size_t capacity) { clearValue(v); v.type = tAttrs; - v.attrs = Bindings::NewGC(); + v.attrs = Bindings::NewGC(capacity); nrAttrsets++; nrAttrsInAttrsets += capacity; } |