[GitHub] [arrow-datafusion] alamb commented on a diff in pull request #6498: feat: datafusion-cli support executes sql with escaped characters

["alamb (via GitHub)" <gi...@apache.org>]

alamb commented on code in PR #6498:
URL: https://github.com/apache/arrow-datafusion/pull/6498#discussion_r1212953521


##########
datafusion-cli/src/helper.rs:
##########
@@ -76,27 +110,117 @@ impl Completer for CliHelper {
 impl Validator for CliHelper {
     fn validate(&self, ctx: &mut ValidationContext<'_>) -> Result<ValidationResult> {
         let input = ctx.input().trim_end();
-        if let Some(sql) = input.strip_suffix(';') {
-            match DFParser::parse_sql(sql) {
-                Ok(statements) if statements.is_empty() => Ok(ValidationResult::Invalid(
-                    Some("  🤔 You entered an empty statement".to_string()),
-                )),
-                Ok(statements) if statements.len() > 1 => Ok(ValidationResult::Invalid(
-                    Some("  🤔 You entered more than one statement".to_string()),
-                )),
-                Ok(_statements) => Ok(ValidationResult::Valid(None)),
-                Err(err) => Ok(ValidationResult::Invalid(Some(format!(
-                    "  🤔 Invalid statement: {}",
-                    err
-                )))),
+        self.validate_input(input)
+    }
+}
+
+impl Helper for CliHelper {}
+
+/// Unescape input string from readline.
+///
+/// The data read from stdio will be escaped, so we need to unescape the input before executing the input
+pub fn unescape_input(input: &str) -> datafusion::error::Result<String> {
+    let mut chars = input.chars();
+
+    let mut result = String::with_capacity(input.len());
+    while let Some(char) = chars.next() {
+        if char == '\\' {
+            if let Some(next_char) = chars.next() {
+                // https://static.rust-lang.org/doc/master/reference.html#literals
+                result.push(match next_char {
+                    '0' => '\0',
+                    'n' => '\n',
+                    'r' => '\r',
+                    't' => '\t',
+                    '\\' => '\\',
+                    _ => {
+                        return Err(DataFusionError::SQL(ParserError::TokenizerError(
+                            format!("unsupported escape char: '\\{}'", next_char),
+                        )))
+                    }
+                });
             }
-        } else if input.starts_with('\\') {
-            // command
-            Ok(ValidationResult::Valid(None))
         } else {
-            Ok(ValidationResult::Incomplete)
+            result.push(char);
         }
     }
+
+    Ok(result)
 }
 
-impl Helper for CliHelper {}
+#[cfg(test)]
+mod tests {
+    use std::io::{BufRead, Cursor};
+
+    use super::*;
+
+    fn readline_direct(
+        mut reader: impl BufRead,
+        validator: &CliHelper,
+    ) -> Result<ValidationResult> {
+        let mut input = String::new();
+
+        if reader.read_line(&mut input)? == 0 {
+            return Err(ReadlineError::Eof);
+        }
+
+        validator.validate_input(&input)
+    }
+
+    #[test]
+    fn unescape_readline_input() -> Result<()> {

Review Comment:
   ❤️ 



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