feat:add if_none_match for write

Signed-off-by: LeeHao <HaozzaLi@gmail.com>

core/src/raw/ops.rs

@@ -581,6 +581,7 @@ pub struct OpWrite {
     content_disposition: Option<String>,
     cache_control: Option<String>,
     executor: Option<Executor>,
+    if_none_match: Option<String>,
     user_metadata: Option<HashMap<String, String>>,
 }
 
@@ -666,6 +667,17 @@ impl OpWrite {
         self
     }
 
+    /// Set the If-None-Match of the option
+    pub fn with_if_none_match(mut self, s: &str) -> Self {
+        self.if_none_match = Some(s.to_string());
+        self
+    }
+
+    /// Get If-None-Match from option
+    pub fn if_none_match(&self) -> Option<&str> {
+        self.if_none_match.as_deref()
+    }
+
     /// Merge given executor into option.
     ///
     /// If executor has already been set, this will do nothing.

core/src/services/s3/core.rs

@@ -474,6 +474,10 @@ impl S3Core {
             req = self.insert_checksum_header(req, &checksum);
         }
 
+        if let Some(if_none_match) = args.if_none_match() {
+            req = req.header(IF_NONE_MATCH, if_none_match);
+        }
+
         // Set body
         let req = req.body(body).map_err(new_request_build_error)?;
 

core/src/types/operator/operator.rs

@@ -1201,6 +1201,26 @@ impl Operator {
     /// # }
     /// ```
     ///
+    /// ## `if_none_match`
+    ///
+    /// Set `if_none_match` for this `write` request.
+    ///
+    /// This feature can be used to check if the file already exists.
+    /// This prevents overwriting of existing objects with identical key names.
+    /// And must use the * (asterisk) value with this parameter
+    ///
+    /// If file exists, an error with kind [`ErrorKind::ConditionNotMatch`] will be returned.
+    ///
+    /// ```no_run
+    /// # use opendal::Result;
+    /// use opendal::Operator;
+    /// # async fn test(op: Operator, etag: &str) -> Result<()> {
+    /// let bs = b"hello, world!".to_vec();
+    /// let mut metadata = op.write_with("path/to/file", bs).if_none_match("*").await?;
+    /// # Ok(())
+    /// # }
+    /// ```
+    ///
     /// # Examples
     ///
     /// ```
@@ -1244,7 +1264,7 @@ impl Operator {
                 }
 
                 let context = WriteContext::new(inner, path, args, options);
-                let mut w = Writer::new(context).await?;
+                let mut w = Writer::new(context).await?;  // 这个函数就会调用S3的write函数
                 w.write(bs).await?;
                 w.close().await?;
                 Ok(())

core/src/types/operator/operator_futures.rs

@@ -324,6 +324,11 @@ impl<F: Future<Output = Result<()>>> FutureWrite<F> {
         self.map(|(args, options, bs)| (args.with_executor(executor), options, bs))
     }
 
+    /// Set the If-None-Match for this operation.
+    pub fn if_none_match(self, s: &str) -> Self {
+        self.map(|(args, options, bs)| (args.with_if_none_match(s), options, bs))
+    }
+
     /// Set the user defined metadata of the op
     ///
     /// ## Notes