Transition PrefValueMap to use std::string_view.

No functionality changes - this is a pure replacement of const
std::string& parameters by std::string_view parameters.

Bug: 348307659
Change-Id: I5ba0658bcb4e68a5f20948d699898bfcd974bc82
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5640036
Commit-Queue: Jan Keitel <jkeitel@google.com>
Reviewed-by: Dominic Battré <battre@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1317292}

components/prefs/pref_value_map.cc

@@ -41,8 +41,14 @@ bool PrefValueMap::GetValue(std::string_view key, base::Value** value) {
   return true;
 }
 
-bool PrefValueMap::SetValue(const std::string& key, base::Value value) {
-  base::Value& existing_value = prefs_[key];
+bool PrefValueMap::SetValue(std::string_view key, base::Value value) {
+  // Once C++26 is supported, just do `base::Value& existing_value =
+  // prefs_[key]`.
+  auto it = prefs_.find(key);
+  if (it == prefs_.end()) {
+    it = prefs_.insert({std::string(key), base::Value()}).first;
+  }
+  base::Value& existing_value = it->second;
   if (value == existing_value)
     return false;
 
@@ -50,19 +56,25 @@ bool PrefValueMap::SetValue(const std::string& key, base::Value value) {
   return true;
 }
 
-bool PrefValueMap::RemoveValue(const std::string& key) {
-  return prefs_.erase(key) != 0;
+bool PrefValueMap::RemoveValue(std::string_view key) {
+  // Once C++23 is supported, just do `return prefs_.erase(key)`;
+  auto it = prefs_.find(key);
+  if (it == prefs_.end()) {
+    return false;
+  }
+  prefs_.erase(it);
+  return true;
 }
 
 void PrefValueMap::Clear() {
   prefs_.clear();
 }
 
-void PrefValueMap::ClearWithPrefix(const std::string& prefix) {
+void PrefValueMap::ClearWithPrefix(std::string_view prefix) {
   Map::iterator low = prefs_.lower_bound(prefix);
   // Appending maximum possible character so that there will be no string with
   // prefix |prefix| that we may miss.
-  Map::iterator high = prefs_.upper_bound(prefix + char(CHAR_MAX));
+  Map::iterator high = prefs_.upper_bound(std::string(prefix) + char(CHAR_MAX));
   prefs_.erase(low, high);
 }
 
@@ -90,7 +102,7 @@ bool PrefValueMap::empty() const {
   return prefs_.empty();
 }
 
-bool PrefValueMap::GetBoolean(const std::string& key, bool* value) const {
+bool PrefValueMap::GetBoolean(std::string_view key, bool* value) const {
   const base::Value* stored_value = nullptr;
   if (GetValue(key, &stored_value) && stored_value->is_bool()) {
     *value = stored_value->GetBool();
@@ -99,11 +111,11 @@ bool PrefValueMap::GetBoolean(const std::string& key, bool* value) const {
   return false;
 }
 
-void PrefValueMap::SetBoolean(const std::string& key, bool value) {
+void PrefValueMap::SetBoolean(std::string_view key, bool value) {
   SetValue(key, base::Value(value));
 }
 
-bool PrefValueMap::GetString(const std::string& key, std::string* value) const {
+bool PrefValueMap::GetString(std::string_view key, std::string* value) const {
   const base::Value* stored_value = nullptr;
   if (GetValue(key, &stored_value) && stored_value->is_string()) {
     *value = stored_value->GetString();
@@ -112,11 +124,11 @@ bool PrefValueMap::GetString(const std::string& key, std::string* value) const {
   return false;
 }
 
-void PrefValueMap::SetString(const std::string& key, const std::string& value) {
+void PrefValueMap::SetString(std::string_view key, std::string_view value) {
   SetValue(key, base::Value(value));
 }
 
-bool PrefValueMap::GetInteger(const std::string& key, int* value) const {
+bool PrefValueMap::GetInteger(std::string_view key, int* value) const {
   const base::Value* stored_value = nullptr;
   if (GetValue(key, &stored_value) && stored_value->is_int()) {
     *value = stored_value->GetInt();
@@ -125,11 +137,11 @@ bool PrefValueMap::GetInteger(const std::string& key, int* value) const {
   return false;
 }
 
-void PrefValueMap::SetInteger(const std::string& key, const int value) {
+void PrefValueMap::SetInteger(std::string_view key, const int value) {
   SetValue(key, base::Value(value));
 }
 
-void PrefValueMap::SetDouble(const std::string& key, const double value) {
+void PrefValueMap::SetDouble(std::string_view key, const double value) {
   SetValue(key, base::Value(value));
 }
 

components/prefs/pref_value_map.h

@@ -27,24 +27,24 @@ class COMPONENTS_PREFS_EXPORT PrefValueMap {
 
   virtual ~PrefValueMap();
 
-  // Gets the value for |key| and stores it in |value|. Ownership remains with
-  // the map. Returns true if a value is present. If not, |value| is not
+  // Gets the value for `key` and stores it in `value`. Ownership remains with
+  // the map. Returns true if a value is present. If not, `value` is not
   // touched.
   bool GetValue(std::string_view key, const base::Value** value) const;
   bool GetValue(std::string_view key, base::Value** value);
 
-  // Sets a new |value| for |key|. Returns true if the value changed.
-  bool SetValue(const std::string& key, base::Value value);
+  // Sets a new `value` for `key`. Returns true if the value changed.
+  bool SetValue(std::string_view key, base::Value value);
 
-  // Removes the value for |key| from the map. Returns true if a value was
+  // Removes the value for `key` from the map. Returns true if a value was
   // removed.
-  bool RemoveValue(const std::string& key);
+  bool RemoveValue(std::string_view key);
 
   // Clears the map.
   void Clear();
 
-  // Clear the preferences which start with |prefix|.
-  void ClearWithPrefix(const std::string& prefix);
+  // Clear the preferences which start with `prefix`.
+  void ClearWithPrefix(std::string_view prefix);
 
   // Swaps the contents of two maps.
   void Swap(PrefValueMap* other);
@@ -55,32 +55,32 @@ class COMPONENTS_PREFS_EXPORT PrefValueMap {
   const_iterator end() const;
   bool empty() const;
 
-  // Gets a boolean value for |key| and stores it in |value|. Returns true if
+  // Gets a boolean value for `key` and stores it in `value`. Returns true if
   // the value was found and of the proper type.
-  bool GetBoolean(const std::string& key, bool* value) const;
+  bool GetBoolean(std::string_view key, bool* value) const;
 
-  // Sets the value for |key| to the boolean |value|.
-  void SetBoolean(const std::string& key, bool value);
+  // Sets the value for `key` to the boolean `value`.
+  void SetBoolean(std::string_view key, bool value);
 
-  // Gets a string value for |key| and stores it in |value|. Returns true if
+  // Gets a string value for `key` and stores it in `value`. Returns true if
   // the value was found and of the proper type.
-  bool GetString(const std::string& key, std::string* value) const;
+  bool GetString(std::string_view key, std::string* value) const;
 
-  // Sets the value for |key| to the string |value|.
-  void SetString(const std::string& key, const std::string& value);
+  // Sets the value for `key` to the string `value`.
+  void SetString(std::string_view key, std::string_view value);
 
-  // Gets an int value for |key| and stores it in |value|. Returns true if
+  // Gets an int value for `key` and stores it in `value`. Returns true if
   // the value was found and of the proper type.
-  bool GetInteger(const std::string& key, int* value) const;
+  bool GetInteger(std::string_view key, int* value) const;
 
-  // Sets the value for |key| to the int |value|.
-  void SetInteger(const std::string& key, const int value);
+  // Sets the value for `key` to the int `value`.
+  void SetInteger(std::string_view key, const int value);
 
-  // Sets the value for |key| to the double |value|.
-  void SetDouble(const std::string& key, const double value);
+  // Sets the value for `key` to the double `value`.
+  void SetDouble(std::string_view key, const double value);
 
-  // Compares this value map against |other| and stores all key names that have
-  // different values in |differing_keys|. This includes keys that are present
+  // Compares this value map against `other` and stores all key names that have
+  // different values in `differing_keys`. This includes keys that are present
   // only in one of the maps.
   void GetDifferingKeys(const PrefValueMap* other,
                         std::vector<std::string>* differing_keys) const;