From fb6540eb5df9e4ece2a4f413366de7de4e08f66c Mon Sep 17 00:00:00 2001
From: Leviathan <leviathan0992@gmail.com>
Date: Wed, 17 Jan 2018 10:42:40 +0800
Subject: [PATCH] add Setnx() and Append() (#1)
MIME-Version: 1.0
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* add examples

* add Setnx() and Append()

* bugfix add the lock before Put()

* bugfix logic errors“
---
 .gitignore                      |  2 ++
 examples/strings_example.cc     | 18 ++++++++++++
 include/blackwidow/blackwidow.h |  2 ++
 src/blackwidow.cc               |  8 ++++++
 src/redis_strings.cc            | 50 +++++++++++++++++++++++++++++++++
 src/redis_strings.h             |  2 ++
 6 files changed, 82 insertions(+)

diff --git a/.gitignore b/.gitignore
index 13f03ed23a..25b113db35 100644
--- a/.gitignore
+++ b/.gitignore
@@ -34,3 +34,5 @@
 # Others
 tags
 src/build_version.cc
+examples/strings_example
+examples/db
diff --git a/examples/strings_example.cc b/examples/strings_example.cc
index a1a47a4322..c4aa2570f1 100644
--- a/examples/strings_example.cc
+++ b/examples/strings_example.cc
@@ -18,16 +18,34 @@ int main() {
     printf("Open failed, error: %s\n", s.ToString().c_str());
     return -1;
   }
+  // Set
   s = db.Set("TEST_KEY", "TEST_VALUE");
   printf("Set return: %s\n", s.ToString().c_str());
+
+  // Get
   std::string value;
   s = db.Get("TEST_KEY", &value);
   printf("Get return: %s, value: %s\n", s.ToString().c_str(), value.c_str());
+
+  // Setnx
+  int32_t ret;
+  s = db.Setnx("TEST_KEY", "TEST_VALUE", &ret);
+  printf("Setnx return: %s, value: %s, ret: %d\n", s.ToString().c_str(), value.c_str(), ret);
+
+  // Append
+  std::string append_value;
+  s = db.Append("TEST_KEY", "APPEND_VALUE", &ret);
+  s = db.Get("TEST_KEY", &append_value);
+  printf("Append return: %s, value: %s, ret: %d\n", s.ToString().c_str(), append_value.c_str(), ret);
+
+  // Expire
   s = db.Expire("TEST_KEY", 1);
   printf("Expire return: %s\n", s.ToString().c_str());
   std::this_thread::sleep_for(std::chrono::milliseconds(2500));
   s = db.Get("TEST_KEY", &value);
   printf("Get return: %s, value: %s\n", s.ToString().c_str(), value.c_str());
+
+  // Compact
   s = db.Compact();
   printf("Compact return: %s\n", s.ToString().c_str());
 
diff --git a/include/blackwidow/blackwidow.h b/include/blackwidow/blackwidow.h
index e4f6ee0ce0..920a1a640b 100644
--- a/include/blackwidow/blackwidow.h
+++ b/include/blackwidow/blackwidow.h
@@ -31,6 +31,8 @@ class BlackWidow {
   // Strings Commands
   Status Set(const Slice& key, const Slice& value);
   Status Get(const Slice& key, std::string* value);
+  Status Setnx(const Slice& key, const Slice& value, int32_t* ret);
+  Status Append(const Slice& key, const Slice& value, int32_t* ret);
 
   // Keys Commands
   Status Expire(const Slice& key, int32_t ttl);
diff --git a/src/blackwidow.cc b/src/blackwidow.cc
index 11d38b760b..2d070637ff 100644
--- a/src/blackwidow.cc
+++ b/src/blackwidow.cc
@@ -45,6 +45,14 @@ Status BlackWidow::Get(const Slice& key, std::string* value) {
   return strings_db_->Get(key, value);
 }
 
+Status BlackWidow::Setnx(const Slice& key, const Slice& value, int32_t* ret) {
+  return strings_db_->Setnx(key, value, ret);
+}
+
+Status BlackWidow::Append(const Slice& key, const Slice& value, int32_t* ret) {
+  return strings_db_->Append(key, value, ret);
+}
+
 Status BlackWidow::Expire(const Slice& key, int32_t ttl) {
   return strings_db_->Expire(key, ttl);
 }
diff --git a/src/redis_strings.cc b/src/redis_strings.cc
index 02fc629e2a..074e81df10 100644
--- a/src/redis_strings.cc
+++ b/src/redis_strings.cc
@@ -39,6 +39,56 @@ Status RedisStrings::Get(const Slice& key, std::string* value) {
   return s;
 }
 
+Status RedisStrings::Setnx(const Slice& key, const Slice& value, int32_t* ret) {
+  *ret = 0;
+  std::string old_value;
+  ScopeRecordLock l(lock_mgr_, key);
+  Status s = db_->Get(default_read_options_, key, &old_value);
+  if (s.ok()) {
+    ParsedInternalStringsValue internal_value(&old_value);
+    if (internal_value.IsStale()) {
+      InternalStringsValue new_value(value);
+      s = db_->Put(default_write_options_, key, new_value.Encode());
+      if (s.ok()) {
+        *ret = 1;
+      }
+    }
+  } else if (s.IsNotFound()) {
+    InternalStringsValue new_value(value);
+    s = db_->Put(default_write_options_, key, new_value.Encode());
+    if (s.ok()) {
+      *ret = 1;
+    }
+  }
+  return s;
+}
+
+Status RedisStrings::Append(const Slice& key, const Slice& value, int32_t* ret) {
+  std::string old_value;
+  *ret = 0;
+  ScopeRecordLock l(lock_mgr_, key);
+  Status s = db_->Get(default_read_options_, key, &old_value);
+  if (s.ok()) {
+    ParsedInternalStringsValue internal_value(&old_value);
+    if (internal_value.IsStale()) {
+      *ret = value.size();
+      InternalStringsValue new_value(value);
+      return db_->Put(default_write_options_, key, new_value.Encode());
+    } else {
+      internal_value.StripSuffix();
+      *ret = old_value.size() + value.size();
+      old_value += value.data();
+      InternalStringsValue new_value(old_value);
+      return db_->Put(default_write_options_, key, new_value.Encode());
+    }
+  } else if (s.IsNotFound()) {
+    *ret = value.size();
+    InternalStringsValue internal_value(value);
+    return db_->Put(default_write_options_, key, internal_value.Encode());
+  }
+  return s;
+}
+
 Status RedisStrings::Expire(const Slice& key, int32_t ttl) {
   std::string value;
   ScopeRecordLock l(lock_mgr_, key);
diff --git a/src/redis_strings.h b/src/redis_strings.h
index 5fe48d5fd3..5031832a44 100644
--- a/src/redis_strings.h
+++ b/src/redis_strings.h
@@ -21,6 +21,8 @@ class RedisStrings : public Redis {
   // Strings Commands
   Status Set(const Slice& key, const Slice& value);
   Status Get(const Slice& key, std::string* value);
+  Status Setnx(const Slice& key, const Slice& value, int32_t* ret);
+  Status Append(const Slice& key, const Slice& value, int32_t* ret);
 
   // Common Commands
   virtual Status Open(const rocksdb::Options& options,