Introduce own mutex for LocaleListCache

To be independent from gMinikinLock, introduce own private mutex for
guarding mLocaleLists and mLocaleListLookupTable.

Here is a raw performance score of walleye-userdebug.

StaticLayout creation time:
 MeasuredText Balanced Hyphenation  :    702,095 ->    707,951: (+0.8%)
 MeasuredText Balanced NoHyphenation:    534,731 ->    532,958: (-0.3%)
 MeasuredText Greedy Hyphenation    :    483,748 ->    491,997: (+1.7%)
 MeasuredText Greedy NoHyphenation  :    486,470 ->    487,135: (+0.1%)
 RandomText Balanced Hyphenation    : 18,092,188 -> 17,977,875: (-0.6%)
 RandomText Balanced NoHyphenation  :  7,622,978 ->  7,545,116: (-1.0%)
 RandomText Greedy Hyphenation      :  7,535,832 ->  7,489,916: (-0.6%)
 RandomText Greedy NoHyphenation    :  7,541,479 ->  7,546,804: (+0.1%)

MeasuredText creation time:
 NoStyled Hyphenation               : 17,957,290 -> 17,925,636: (-0.2%)
 NoStyled Hyphenation WidthOnly     : 17,526,213 -> 17,427,896: (-0.6%)
 NoStyled NoHyphenation             :  7,541,455 ->  7,532,890: (-0.1%)
 NoStyled NoHyphenation WidthOnly   :  7,128,731 ->  7,082,616: (-0.6%)
 Styled Hyphenation                 : 14,843,198 -> 14,738,258: (-0.7%)
 Styled Hyphenation WidthOnly       : 13,880,962 -> 13,858,992: (-0.2%)
 Styled NoHyphenation               : 14,393,544 -> 14,365,111: (-0.2%)
 Styled NoHyphenation WidthOnly     : 13,497,007 -> 13,504,562: (+0.1%)

StaticLayout draw time:
 MeasuredText NoStyled              :    666,351 ->    657,886: (-1.3%)
 MeasuredText NoStyled WithoutCache :    655,528 ->    658,249: (+0.4%)
 MeasuredText Styled                :    865,664 ->    869,500: (+0.4%)
 MeasuredText Styled WithoutCache   :    901,887 ->    900,078: (-0.2%)
 RandomText NoStyled                :    576,268 ->    575,145: (-0.2%)
 RandomText NoStyled WithoutCache   :  6,899,642 ->  6,819,789: (-1.2%)
 RandomText Styled                  :  2,936,847 ->  2,929,798: (-0.2%)
 RandomText Styled WithoutCache     :  3,395,033 ->  3,411,809: (+0.5%)

Bug: 37567215
Test: minikin_tests

Change-Id: I7f55be10355fd34a02ea91bf67e0810079f30405

2 files changed, 37 insertions, 33 deletions

diff --git a/libs/minikin/LocaleListCache.cpp b/libs/minikin/LocaleListCache.cpp
index 625b4d2..c191ea6 100644
--- a/libs/minikin/LocaleListCache.cpp
+++ b/libs/minikin/LocaleListCache.cpp
@@ -103,46 +103,35 @@ static std::vector<Locale> parseLocaleList(const std::string& input) {
     return result;
 }
 
-// static
-uint32_t LocaleListCache::getId(const std::string& locales) {
-    LocaleListCache* inst = LocaleListCache::getInstance();
-    std::unordered_map<std::string, uint32_t>::const_iterator it =
-            inst->mLocaleListLookupTable.find(locales);
-    if (it != inst->mLocaleListLookupTable.end()) {
+LocaleListCache::LocaleListCache() {
+    // Insert an empty locale list for mapping default locale list to kEmptyListId.
+    // The default locale list has only one Locale and it is the unsupported locale.
+    mLocaleLists.emplace_back();
+    mLocaleListLookupTable.insert(std::make_pair("", kEmptyListId));
+}
+
+uint32_t LocaleListCache::getIdInternal(const std::string& locales) {
+    std::lock_guard<std::mutex> lock(mMutex);
+    const auto& it = mLocaleListLookupTable.find(locales);
+    if (it != mLocaleListLookupTable.end()) {
         return it->second;
     }
 
     // Given locale list is not in cache. Insert it and return newly assigned ID.
-    const uint32_t nextId = inst->mLocaleLists.size();
+    const uint32_t nextId = mLocaleLists.size();
     LocaleList fontLocales(parseLocaleList(locales));
     if (fontLocales.empty()) {
         return kEmptyListId;
     }
-    inst->mLocaleLists.push_back(std::move(fontLocales));
-    inst->mLocaleListLookupTable.insert(std::make_pair(locales, nextId));
+    mLocaleLists.push_back(std::move(fontLocales));
+    mLocaleListLookupTable.insert(std::make_pair(locales, nextId));
     return nextId;
 }
 
-// static
-const LocaleList& LocaleListCache::getById(uint32_t id) {
-    LocaleListCache* inst = LocaleListCache::getInstance();
-    MINIKIN_ASSERT(id < inst->mLocaleLists.size(), "Lookup by unknown locale list ID.");
-    return inst->mLocaleLists[id];
-}
-
-// static
-LocaleListCache* LocaleListCache::getInstance() {
-    assertMinikinLocked();
-    static LocaleListCache* instance = nullptr;
-    if (instance == nullptr) {
-        instance = new LocaleListCache();
-
-        // Insert an empty locale list for mapping default locale list to kEmptyListId.
-        // The default locale list has only one Locale and it is the unsupported locale.
-        instance->mLocaleLists.push_back(LocaleList());
-        instance->mLocaleListLookupTable.insert(std::make_pair("", kEmptyListId));
-    }
-    return instance;
+const LocaleList& LocaleListCache::getByIdInternal(uint32_t id) {
+    std::lock_guard<std::mutex> lock(mMutex);
+    MINIKIN_ASSERT(id < mLocaleLists.size(), "Lookup by unknown locale list ID.");
+    return mLocaleLists[id];
 }
 
 }  // namespace minikin
diff --git a/libs/minikin/LocaleListCache.h b/libs/minikin/LocaleListCache.h
index 9ebb111..2a007af 100644
--- a/libs/minikin/LocaleListCache.h
+++ b/libs/minikin/LocaleListCache.h
@@ -17,6 +17,7 @@
 #ifndef MINIKIN_LOCALE_LIST_CACHE_H
 #define MINIKIN_LOCALE_LIST_CACHE_H
 
+#include <mutex>
 #include <unordered_map>
 
 #include "Locale.h"
@@ -35,22 +36,36 @@ public:
 
     // Returns the locale list ID for the given string representation of LocaleList.
     // Caller should acquire a lock before calling the method.
-    static uint32_t getId(const std::string& locales);
+    static inline uint32_t getId(const std::string& locales) {
+        return getInstance().getIdInternal(locales);
+    }
 
     // Caller should acquire a lock before calling the method.
-    static const LocaleList& getById(uint32_t id);
+    static inline const LocaleList& getById(uint32_t id) {
+        return getInstance().getByIdInternal(id);
+    }
 
 private:
-    LocaleListCache() {}  // Singleton
+    LocaleListCache();  // Singleton
     ~LocaleListCache() {}
 
+    uint32_t getIdInternal(const std::string& locales);
+    const LocaleList& getByIdInternal(uint32_t id);
+
     // Caller should acquire a lock before calling the method.
-    static LocaleListCache* getInstance();
+    static LocaleListCache& getInstance() {
+        static LocaleListCache instance;
+        return instance;
+    }
 
     std::vector<LocaleList> mLocaleLists;
 
     // A map from the string representation of the font locale list to the ID.
     std::unordered_map<std::string, uint32_t> mLocaleListLookupTable;
+
+    // To avoid dead-locking, need to acquire gMinikinLock before acquiring mMutex.
+    // TODO: Remove gMinikinLock
+    std::mutex mMutex;
 };
 
 }  // namespace minikin