Fix SkTArray operator= to work with self assignment

BUG=skia:

Change-Id: I2a403a7ccbb87a030757f3e57d2ea53503f72512
Reviewed-on: https://skia-review.googlesource.com/10012
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>

2 files changed, 21 insertions, 0 deletions

diff --git a/include/private/SkTArray.h b/include/private/SkTArray.h
index fdf96c87bc..4b700d2d29 100644
--- a/include/private/SkTArray.h
+++ b/include/private/SkTArray.h
@@ -59,6 +59,9 @@ public:
     }
 
     SkTArray& operator=(const SkTArray& that) {
+        if (this == &that) {
+            return *this;
+        }
         for (int i = 0; i < fCount; ++i) {
             fItemArray[i].~T();
         }
@@ -69,6 +72,9 @@ public:
         return *this;
     }
     SkTArray& operator=(SkTArray&& that) {
+        if (this == &that) {
+            return *this;
+        }
         for (int i = 0; i < fCount; ++i) {
             fItemArray[i].~T();
         }
diff --git a/tests/TArrayTest.cpp b/tests/TArrayTest.cpp
index 6e23c49b35..0e18e9f96d 100644
--- a/tests/TArrayTest.cpp
+++ b/tests/TArrayTest.cpp
@@ -281,6 +281,19 @@ void test_unnecessary_alloc(skiatest::Reporter* reporter) {
     }
 }
 
+static void test_self_assignment(skiatest::Reporter* reporter) {
+    SkTArray<int> a;
+    a.push_back(1);
+    REPORTER_ASSERT(reporter, !a.empty());
+    REPORTER_ASSERT(reporter, a.count() == 1);
+    REPORTER_ASSERT(reporter, a[0] == 1);
+
+    a = a;
+    REPORTER_ASSERT(reporter, !a.empty());
+    REPORTER_ASSERT(reporter, a.count() == 1);
+    REPORTER_ASSERT(reporter, a[0] == 1);
+}
+
 DEF_TEST(TArray, reporter) {
     TestTSet_basic<true>(reporter);
     TestTSet_basic<false>(reporter);
@@ -296,4 +309,6 @@ DEF_TEST(TArray, reporter) {
     test_move(reporter);
 
     test_unnecessary_alloc(reporter);
+
+    test_self_assignment(reporter);
 }