Improve RE2::Set and FilteredRE2 move semantics.

Change-Id: I59ad2893e2900a238edf7ecfcf68ca7473215e09 Reviewed-on: https://code-review.googlesource.com/c/re2/+/57430 Reviewed-by: Paul Wankadia <[email protected]>
google · Jun 18, 2020 · f294a9f · f294a9f
1 parent e6613e9
commit f294a9f
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Showing 4 changed files with 40 additions and 8 deletions.
diff --git a/re2/filtered_re2.cc b/re2/filtered_re2.cc
@@ -6,6 +6,7 @@
 
 #include <stddef.h>
 #include <string>
+#include <utility>
 
 #include "util/util.h"
 #include "util/logging.h"
@@ -29,8 +30,21 @@ FilteredRE2::~FilteredRE2() {
     delete re2_vec_[i];
 }
 
-FilteredRE2::FilteredRE2(FilteredRE2&&) = default;
-FilteredRE2& FilteredRE2::operator=(FilteredRE2&&) = default;
+FilteredRE2::FilteredRE2(FilteredRE2&& other)
+    : re2_vec_(std::move(other.re2_vec_)),
+      compiled_(other.compiled_),
+      prefilter_tree_(std::move(other.prefilter_tree_)) {
+  other.re2_vec_.clear();
+  other.re2_vec_.shrink_to_fit();
+  other.compiled_ = false;
+  other.prefilter_tree_.reset(new PrefilterTree());
+}
+
+FilteredRE2& FilteredRE2::operator=(FilteredRE2&& other) {
+  this->~FilteredRE2();
+  (void) new (this) FilteredRE2(std::move(other));
+  return *this;
+}
 
 RE2::ErrorCode FilteredRE2::Add(const StringPiece& pattern,
                                 const RE2::Options& options, int* id) {

diff --git a/re2/filtered_re2.h b/re2/filtered_re2.h
@@ -41,8 +41,8 @@ class FilteredRE2 {
   FilteredRE2(const FilteredRE2&) = delete;
   FilteredRE2& operator=(const FilteredRE2&) = delete;
   // Movable.
-  FilteredRE2(FilteredRE2&&);
-  FilteredRE2& operator=(FilteredRE2&&);
+  FilteredRE2(FilteredRE2&& other);
+  FilteredRE2& operator=(FilteredRE2&& other);
 
   // Uses RE2 constructor to create a RE2 object (re). Returns
   // re->error_code(). If error_code is other than NoError, then re is

diff --git a/re2/set.cc b/re2/set.cc
@@ -7,6 +7,7 @@
 #include <stddef.h>
 #include <algorithm>
 #include <memory>
+#include <utility>
 
 #include "util/util.h"
 #include "util/logging.h"
@@ -31,8 +32,25 @@ RE2::Set::~Set() {
     elem_[i].second->Decref();
 }
 
-RE2::Set::Set(Set&&) = default;
-RE2::Set& RE2::Set::operator=(Set&&) = default;
+RE2::Set::Set(Set&& other)
+    : options_(other.options_),
+      anchor_(other.anchor_),
+      elem_(std::move(other.elem_)),
+      compiled_(other.compiled_),
+      size_(other.size_),
+      prog_(std::move(other.prog_)) {
+  other.elem_.clear();
+  other.elem_.shrink_to_fit();
+  other.compiled_ = false;
+  other.size_ = 0;
+  other.prog_.reset();
+}
+
+RE2::Set& RE2::Set::operator=(Set&& other) {
+  this->~Set();
+  (void) new (this) Set(std::move(other));
+  return *this;
+}
 
 int RE2::Set::Add(const StringPiece& pattern, std::string* error) {
   if (compiled_) {

diff --git a/re2/set.h b/re2/set.h
@@ -41,8 +41,8 @@ class RE2::Set {
   Set(const Set&) = delete;
   Set& operator=(const Set&) = delete;
   // Movable.
-  Set(Set&&);
-  Set& operator=(Set&&);
+  Set(Set&& other);
+  Set& operator=(Set&& other);
 
   // Adds pattern to the set using the options passed to the constructor.
   // Returns the index that will identify the regexp in the output of Match(),