feat(server): SCAN command add ATTR options (#4766)

src/server/common.cc

@@ -308,6 +308,19 @@ OpResult<ScanOpts> ScanOpts::TryFrom(CmdArgList args) {
       if (!absl::SimpleAtoi(ArgS(args, i + 1), &scan_opts.bucket_id)) {
         return facade::OpStatus::INVALID_INT;
       }
+    } else if (opt == "ATTR") {
+      string_view mask = ArgS(args, i + 1);
+      if (mask == "v") {
+        scan_opts.mask = ScanOpts::Mask::Volatile;
+      } else if (mask == "p") {
+        scan_opts.mask = ScanOpts::Mask::Permanent;
+      } else if (mask == "a") {
+        scan_opts.mask = ScanOpts::Mask::Accessed;
+      } else if (mask == "u") {
+        scan_opts.mask = ScanOpts::Mask::Untouched;
+      } else {
+        return facade::OpStatus::SYNTAX_ERR;
+      }
     } else {
       return facade::OpStatus::SYNTAX_ERR;
     }

src/server/common.h

@@ -312,6 +312,14 @@ struct ScanOpts {
   size_t limit = 10;
   std::optional<CompactObjType> type_filter;
   unsigned bucket_id = UINT_MAX;
+  enum class Mask {
+    Volatile,   // volatile, keys that have ttl
+    Permanent,  // permanent, keys that do not have ttl
+    Accessed,   // accessed, the key has been accessed since the last load/flush event, or the last
+                // time a flag was reset.
+    Untouched,  // untouched, the key has not been accessed/touched.
+  };
+  std::optional<Mask> mask;
 
   bool Matches(std::string_view val_name) const;
   static OpResult<ScanOpts> TryFrom(CmdArgList args);

src/server/generic_family.cc

@@ -599,7 +599,17 @@ bool ScanCb(const OpArgs& op_args, PrimeIterator prime_it, const ScanOpts& opts,
   }
 
   bool matches = !opts.type_filter || it->second.ObjType() == opts.type_filter;
-
+  if (opts.mask.has_value()) {
+    if (opts.mask == ScanOpts::Mask::Volatile) {
+      matches &= it->second.HasExpire();
+    } else if (opts.mask == ScanOpts::Mask::Permanent) {
+      matches &= !it->second.HasExpire();
+    } else if (opts.mask == ScanOpts::Mask::Accessed) {
+      matches &= it->first.WasTouched();
+    } else if (opts.mask == ScanOpts::Mask::Untouched) {
+      matches &= !it->first.WasTouched();
+    }
+  }
   if (!matches)
     return false;
 
@@ -1747,6 +1757,7 @@ void GenericFamily::Echo(CmdArgList args, const CommandContext& cmd_cntx) {
 }
 
 // SCAN cursor [MATCH <glob>] [TYPE <type>] [COUNT <count>] [BUCKET <bucket_id>]
+// [ATTR <mask>]
 void GenericFamily::Scan(CmdArgList args, const CommandContext& cmd_cntx) {
   string_view token = ArgS(args, 0);
   uint64_t cursor = 0;

src/server/generic_family_test.cc

@@ -412,6 +412,49 @@ TEST_F(GenericFamilyTest, Scan) {
   EXPECT_EQ(resp, "");
 }
 
+TEST_F(GenericFamilyTest, ScanWithAttr) {
+  Run({"flushdb"});
+
+  Run({"set", "hello", "world"});
+  Run({"set", "foo", "bar"});
+
+  Run({"expire", "hello", "1000"});
+
+  auto resp = Run({"scan", "0", "attr", "v"});
+  auto vec = StrArray(resp.GetVec()[1]);
+  ASSERT_EQ(1, vec.size());
+  EXPECT_EQ(vec[0], "hello");
+
+  resp = Run({"scan", "0", "attr", "p"});
+  vec = StrArray(resp.GetVec()[1]);
+  ASSERT_EQ(1, vec.size());
+  EXPECT_EQ(vec[0], "foo");
+
+  // before run get "foo", scan with a attr should return "hello", because set "hello" expire before
+  resp = Run({"scan", "0", "attr", "a"});
+  vec = StrArray(resp.GetVec()[1]);
+  ASSERT_EQ(1, vec.size());
+  EXPECT_EQ(vec[0], "hello");
+
+  // before run get "foo", scan with a attr should return "foo"
+  resp = Run({"scan", "0", "attr", "u"});
+  vec = StrArray(resp.GetVec()[1]);
+  ASSERT_EQ(1, vec.size());
+  EXPECT_EQ(vec[0], "foo");
+
+  ASSERT_THAT(Run({"get", "foo"}), "bar");
+
+  // after run get "foo", scan with a attr should return "foo" and "hello"
+  resp = Run({"scan", "0", "attr", "a"});
+  vec = StrArray(resp.GetVec()[1]);
+  ASSERT_EQ(2, vec.size());
+
+  // after run get "foo", scan with a attr should return empty set
+  resp = Run({"scan", "0", "attr", "u"});
+  vec = StrArray(resp.GetVec()[1]);
+  ASSERT_EQ(0, vec.size());
+}
+
 TEST_F(GenericFamilyTest, Sort) {
   // Test list sort with params
   Run({"del", "list-1"});