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refactor(3p/nix/libexpr): Use absl::btree_map for AttrSets

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This is the first step towards replacing the implementation of
attribute sets with an absl::btree_map.

Currently many access are done using array offsets and pointer
arithmetic, so this change is currently causing Nix to fail in various
ways.
This commit is contained in:
Vincent Ambo 2020-05-21 19:20:24 +01:00
parent 1bb9cd7749
commit 28e347effe
6 changed files with 95 additions and 78 deletions
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51
third_party/nix/src/libexpr/attr-set.cc vendored
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@ -1,22 +1,49 @@
#include "attr-set.hh"
#include <algorithm>
#include <absl/container/btree_map.h>
#include "eval-inline.hh"
namespace nix {
/* Allocate a new array of attributes for an attribute set with a specific
capacity. The space is implicitly reserved after the Bindings
structure. */
Bindings* EvalState::allocBindings(size_t capacity) {
if (capacity > std::numeric_limits<Bindings::size_t>::max()) {
throw Error("attribute set of size %d is too big", capacity);
}
return new (allocBytes(sizeof(Bindings) + sizeof(Attr) * capacity))
Bindings((Bindings::size_t)capacity);
// TODO: using insert_or_assign might break existing Nix code because
// of the weird ordering situation. Need to investigate.
void Bindings::push_back(const Attr& attr) {
attributes_.insert_or_assign(attr.name, attr);
}
size_t Bindings::size() { return attributes_.size(); }
void Bindings::sort() {}
size_t Bindings::capacity() { return 0; }
bool Bindings::empty() { return attributes_.empty(); }
std::vector<const Attr*> Bindings::lexicographicOrder() {
std::vector<const Attr*> res;
res.reserve(attributes_.size());
for (const auto& [key, value] : attributes_) {
res.emplace_back(&value);
}
return res;
}
Bindings::iterator Bindings::find(const Symbol& name) {
return &attributes_[name];
}
Bindings::iterator Bindings::begin() { return &(attributes_.begin()->second); }
Bindings::iterator Bindings::end() { return &(attributes_.end()->second); }
// /* Allocate a new array of attributes for an attribute set with a specific
// capacity. The space is implicitly reserved after the Bindings structure.
// */
Bindings* EvalState::allocBindings(size_t _capacity) { return new Bindings; }
// TODO(tazjin): What's Value? What's going on here?
void EvalState::mkAttrs(Value& v, size_t capacity) {
if (capacity == 0) {
v = vEmptySet;
@ -24,7 +51,7 @@ void EvalState::mkAttrs(Value& v, size_t capacity) {
}
clearValue(v);
v.type = tAttrs;
v.attrs = allocBindings(capacity);
v.attrs = new Bindings;
nrAttrsets++;
nrAttrsInAttrsets += capacity;
}
@ -38,6 +65,6 @@ Value* EvalState::allocAttr(Value& vAttrs, const Symbol& name) {
return v;
}
void Bindings::sort() { std::sort(begin(), end()); }
// void Bindings::sort() { std::sort(begin(), end()); }
} // namespace nix