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authorVincent Ambo <tazjin@google.com>2020-05-21T03·53+0100
committerVincent Ambo <tazjin@google.com>2020-05-21T04·09+0100
commit97e85f94e5ee7e6c8340011757a71222b8091cda (patch)
treeeb46a1e2a1b06508a30f7b46aa050bc51b24d2b6 /third_party/nix/src/libexpr/symbol-table.cc
parent00017ace042d183400be78269e99e2952746cce1 (diff)
refactor(3p/nix/libexpr): Use absl::node_hash_set in SymbolTable r/794
This replaces the previous use of std::unordered_set with
absl::node_hash_set.

This type was chosen because the current implementation requires
pointer stability.

This does not yet touch the 'Attr' struct.

As a bonus, the implementation of the SymbolTable struct is now
consolidated into a single header/implementation file pair.
Diffstat (limited to 'third_party/nix/src/libexpr/symbol-table.cc')
-rw-r--r--third_party/nix/src/libexpr/symbol-table.cc24
1 files changed, 24 insertions, 0 deletions
diff --git a/third_party/nix/src/libexpr/symbol-table.cc b/third_party/nix/src/libexpr/symbol-table.cc
new file mode 100644
index 000000000000..5b9fb27d59aa
--- /dev/null
+++ b/third_party/nix/src/libexpr/symbol-table.cc
@@ -0,0 +1,24 @@
+#include "symbol-table.hh"
+
+#include <absl/container/node_hash_set.h>
+#include <absl/strings/string_view.h>
+
+namespace nix {
+
+Symbol SymbolTable::Create(absl::string_view sym) {
+  auto it = symbols_.emplace(sym);
+  const string* ptr = &(*it.first);
+  return Symbol(ptr);
+}
+
+size_t SymbolTable::Size() const { return symbols_.size(); }
+
+size_t SymbolTable::TotalSize() const {
+  size_t n = 0;
+  for (auto& i : symbols_) {
+    n += i.size();
+  }
+  return n;
+}
+
+}  // namespace nix