Add support to delete hash fields

Author: prashanthpai

src/key.rs

@@ -173,6 +173,10 @@ impl RedisKeyWritable {
         raw::hash_set(self.key_inner, field, value.inner)
     }
 
+    pub fn hash_del(&self, field: &str) -> raw::Status {
+        raw::hash_del(self.key_inner, field)
+    }
+
     pub fn hash_get(&self, field: &str) -> Result<Option<RedisString>, RedisError> {
         Ok(hash_mget_key(self.ctx, self.key_inner, &[field])?
             .pop()

src/raw.rs

@@ -157,6 +157,11 @@ extern "C" {
 
 pub const FMT: *const c_char = b"v\0".as_ptr() as *const c_char;
 
+// REDISMODULE_HASH_DELETE is defined explicitly here because bindgen cannot
+// parse typecasts in C macro constants yet.
+// See https://github.com/rust-lang/rust-bindgen/issues/316
+pub const REDISMODULE_HASH_DELETE: *const RedisModuleString = 1 as *const RedisModuleString;
+
 // Helper functions for the raw bindings.
 
 pub fn call_reply_type(reply: *mut RedisModuleCallReply) -> ReplyType {
@@ -348,6 +353,25 @@ pub fn hash_set(key: *mut RedisModuleKey, field: &str, value: *mut RedisModuleSt
     }
 }
 
+pub fn hash_del(key: *mut RedisModuleKey, field: &str) -> Status {
+    let field = CString::new(field).unwrap();
+
+    // TODO: Add hash_del_multi()
+    // Support to pass multiple fields is desired but is complicated.
+    // See hash_get_multi() and https://github.com/redis/redis/issues/7860
+
+    unsafe {
+        RedisModule_HashSet.unwrap()(
+            key,
+            REDISMODULE_HASH_CFIELDS as i32,
+            field.as_ptr(),
+            REDISMODULE_HASH_DELETE,
+            ptr::null::<c_char>(),
+        )
+        .into()
+    }
+}
+
 // Returns pointer to the C string, and sets len to its length
 pub fn string_ptr_len(s: *mut RedisModuleString, len: *mut size_t) -> *const c_char {
     unsafe { RedisModule_StringPtrLen.unwrap()(s, len) }