Clang: Add file cache

The database is using file path integer ids to handle file paths because
otherwise we would save many redundant data. This patch is improving it
further with the introduction of a database based file path cache. The
entries are now divided in a directory path and file name. This is quite
handy for directory based file watching.

Change-Id: I03f2e388e43f3d521d6bf8e39dfb95eb2309dc73
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

tests/unit/unittest/stringcache-test.cpp

@@ -25,6 +25,9 @@
 
 #include "googletest.h"
 
+#include "mockmutex.h"
+#include "mockfilepathstorage.h"
+
 #include <stringcache.h>
 
 #include <utils/smallstringio.h>
@@ -38,8 +41,15 @@ using uint64 = unsigned long long;
 using Utils::compare;
 using Utils::reverseCompare;
 using ClangBackEnd::findInSorted;
+using StorageIdFunction = std::function<int(Utils::SmallStringView)>;
+using StorageStringFunction = std::function<Utils::PathString(int)>;
 
-using CacheEntries = ClangBackEnd::FileCacheCacheEntries;
+using Cache = ClangBackEnd::StringCache<Utils::PathString,
+                                        int,
+                                        NiceMock<MockMutex>,
+                                        decltype(&Utils::reverseCompare),
+                                        Utils::reverseCompare>;
+using CacheEntries = Cache::CacheEntries;
 
 class StringCache : public testing::Test
 {
@@ -47,7 +57,15 @@ protected:
     void SetUp();
 
 protected:
-    ClangBackEnd::FilePathCache<> cache;
+    NiceMock<MockFilePathStorage> mockStorage;
+    StorageIdFunction mockStorageFetchDirectyId = [&] (Utils::SmallStringView string) {
+        return mockStorage.fetchDirectoryId(string);
+    };
+    StorageStringFunction mockStorageFetchDirectyPath = [&] (int id) {
+        return mockStorage.fetchDirectoryPath(id);
+    };
+    Cache cache;
+    NiceMock<MockMutex> &mockMutex = cache.mutex();
     Utils::PathString filePath1{"/file/pathOne"};
     Utils::PathString filePath2{"/file/pathTwo"};
     Utils::PathString filePath3{"/file/pathThree"};
@@ -311,11 +329,123 @@ TEST_F(StringCache, FindInSortedFifeReverse)
     ASSERT_TRUE(found.wasFound);
 }
 
+TEST_F(StringCache, StringIdIsLocked)
+{
+    EXPECT_CALL(mockMutex, lock());
+    EXPECT_CALL(mockMutex, unlock());
+
+    cache.stringId("foo");
+}
+
+TEST_F(StringCache, StringIdsIsLocked)
+{
+    EXPECT_CALL(mockMutex, lock());
+    EXPECT_CALL(mockMutex, unlock());
+
+    cache.stringIds({"foo"});
+}
+
+TEST_F(StringCache, StringIsLocked)
+{
+    cache.stringId("foo");
+
+    EXPECT_CALL(mockMutex, lock());
+    EXPECT_CALL(mockMutex, unlock());
+
+    cache.string(0);
+}
+
+TEST_F(StringCache, StringsIsLocked)
+{
+    cache.stringId("foo");
+
+    EXPECT_CALL(mockMutex, lock());
+    EXPECT_CALL(mockMutex, unlock());
+
+    cache.strings({0});
+}
+
+TEST_F(StringCache, StringIdWithStorageFunctionIsLocked)
+{
+    EXPECT_CALL(mockMutex, lock());
+    EXPECT_CALL(mockMutex, unlock());
+
+    cache.stringId("foo", mockStorageFetchDirectyId);
+}
+
+TEST_F(StringCache, StringIdWithStorageFunctionWhichHasNoEntryIsCallingStorageFunction)
+{
+    EXPECT_CALL(mockStorage, fetchDirectoryId(Eq("foo")));
+
+    cache.stringId("foo", mockStorageFetchDirectyId);
+}
+
+TEST_F(StringCache, StringIdWithStorageFunctionWhichHasEntryIsNotCallingStorageFunction)
+{
+    cache.stringId("foo", mockStorageFetchDirectyId);
+
+    EXPECT_CALL(mockStorage, fetchDirectoryId(Eq("foo"))).Times(0);
+
+    cache.stringId("foo", mockStorageFetchDirectyId);
+}
+
+TEST_F(StringCache, IndexOfStringIdWithStorageFunctionWhichHasEntry)
+{
+    cache.stringId("foo", mockStorageFetchDirectyId);
+
+    auto index = cache.stringId("foo", mockStorageFetchDirectyId);
+
+    ASSERT_THAT(index, 42);
+}
+
+TEST_F(StringCache, IndexOfStringIdWithStorageFunctionWhichHasNoEntry)
+{
+    auto index = cache.stringId("foo", mockStorageFetchDirectyId);
+
+    ASSERT_THAT(index, 42);
+}
+
+TEST_F(StringCache, GetEntryByIndexAfterInsertingByCustomIndex)
+{
+    auto index = cache.stringId("foo", mockStorageFetchDirectyId);
+
+    auto string = cache.string(index, mockStorageFetchDirectyPath);
+
+    ASSERT_THAT(string, Eq("foo"));
+}
+
+TEST_F(StringCache, CallFetchDirectoryPathForLowerIndex)
+{
+    auto index = cache.stringId("foo", mockStorageFetchDirectyId);
+
+    EXPECT_CALL(mockStorage, fetchDirectoryPath(Eq(index - 1)));
+
+    cache.string(index - 1, mockStorageFetchDirectyPath);
+}
+
+TEST_F(StringCache, CallFetchDirectoryPathForUnknownIndex)
+{
+    EXPECT_CALL(mockStorage, fetchDirectoryPath(Eq(0)));
+
+    cache.string(0, mockStorageFetchDirectyPath);
+}
+
+TEST_F(StringCache, FetchDirectoryPathForUnknownIndex)
+{
+    auto string = cache.string(41, mockStorageFetchDirectyPath);
+
+    ASSERT_THAT(string, Eq("bar"));
+}
 
 void StringCache::SetUp()
 {
     std::sort(filePaths.begin(), filePaths.end(), [] (auto &f, auto &l) { return compare(f, l) < 0;});
     std::sort(reverseFilePaths.begin(), reverseFilePaths.end(), [] (auto &f, auto &l) { return reverseCompare(f, l) < 0;});
+
+    ON_CALL(mockStorage, fetchDirectoryId(Eq("foo")))
+            .WillByDefault(Return(42));
+    ON_CALL(mockStorage, fetchDirectoryPath(41))
+            .WillByDefault(Return(Utils::PathString("bar")));
 }
 }