commit 9351f5d0601788d143fa96994712fba32697aa98
author Kelvin Zhang <zhangkelvin@google.com> Tue Aug 17 19:29:49 2021 -0700
committer Kelvin Zhang <zhangkelvin@google.com> Mon Aug 23 18:51:14 2021 -0700
tree c32e61ca7007044f6ab8600dff9ca28fbf6ace4a
parent be1c1800a6380cd67cef7e25eb96011e84714b18

Implement ExtentLess correctly

If two extents start on the same block but have different number of
blocks, current impl of ExtentLess will consider them equal.

Test: th
Change-Id: Ief147f9d0a91b3dcd7f8ccc690f3aea972cbeabb

payload_consumer/extent_map.h

diff --git a/payload_consumer/extent_map.h b/payload_consumer/extent_map.h
index aeb7066..65f1bcd 100644
--- a/payload_consumer/extent_map.h
+++ b/payload_consumer/extent_map.h
@@ -22,6 +22,7 @@
 #include <utility>
 
 #include "update_engine/common/utils.h"
+#include "update_engine/payload_generator/extent_utils.h"
 #include "update_engine/payload_generator/extent_ranges.h"
 #include "update_engine/update_metadata.pb.h"
 
@@ -35,7 +36,7 @@
 class ExtentMap {
  public:
   bool AddExtent(const Extent& extent, T&& value) {
-    if (Get(extent)) {
+    if (set_.OverlapsWithExtent(extent)) {
       return false;
     }
     const auto& [it, inserted] = map_.insert({extent, std::forward<T>(value)});

payload_consumer/extent_map_unittest.cc

diff --git a/payload_consumer/extent_map_unittest.cc b/payload_consumer/extent_map_unittest.cc
index e7972cd..867038b 100644
--- a/payload_consumer/extent_map_unittest.cc
+++ b/payload_consumer/extent_map_unittest.cc
@@ -119,4 +119,17 @@
   ASSERT_EQ(ret[2].num_blocks(), 2U);
 }
 
+TEST_F(ExtentMapTest, GetSameStartBlock) {
+  ASSERT_TRUE(map_.AddExtent(ExtentForRange(0, 5), 7));
+  ASSERT_TRUE(map_.AddExtent(ExtentForRange(10, 5), 12));
+
+  const auto ret = map_.Get(ExtentForRange(0, 10));
+  // ASSERT_FALSE(ret.has_value()) << ret.value() won't work, because when |ret|
+  // doesn't have value, the part after '<<' after still evaluated, resulting in
+  // undefined behavior.
+  if (ret.has_value()) {
+    FAIL() << ret.value();
+  }
+}
+
 }  // namespace chromeos_update_engine