Implement json_quote

Author: pedrocarlo

core/function.rs

@@ -79,6 +79,7 @@ pub enum JsonFunc {
     JsonObject,
     JsonType,
     JsonErrorPosition,
+    JsonQuote,
 }
 
 #[cfg(feature = "json")]
@@ -97,6 +98,7 @@ impl Display for JsonFunc {
                 Self::JsonObject => "json_object".to_string(),
                 Self::JsonType => "json_type".to_string(),
                 Self::JsonErrorPosition => "json_error_position".to_string(),
+                Self::JsonQuote => "json_quote".to_string(),
             }
         )
     }
@@ -517,6 +519,8 @@ impl Func {
             "json_type" => Ok(Func::Json(JsonFunc::JsonType)),
             #[cfg(feature = "json")]
             "json_error_position" => Ok(Self::Json(JsonFunc::JsonErrorPosition)),
+            #[cfg(feature = "json")]
+            "json_quote" => Ok(Self::Json(JsonFunc::JsonQuote)),
             "unixepoch" => Ok(Self::Scalar(ScalarFunc::UnixEpoch)),
             "julianday" => Ok(Self::Scalar(ScalarFunc::JulianDay)),
             "hex" => Ok(Self::Scalar(ScalarFunc::Hex)),

core/json/mod.rs

@@ -12,6 +12,7 @@ pub use crate::json::ser::to_string;
 use crate::types::{LimboText, OwnedValue, TextSubtype};
 use indexmap::IndexMap;
 use jsonb::Error as JsonbError;
+use ser::escape;
 use serde::{Deserialize, Serialize};
 
 #[derive(Serialize, Deserialize, Debug, PartialEq, Clone)]
@@ -448,6 +449,36 @@ pub fn json_object(values: &[OwnedValue]) -> crate::Result<OwnedValue> {
     Ok(OwnedValue::Text(LimboText::json(Rc::new(result))))
 }
 
+pub fn json_quote(value: &OwnedValue) -> crate::Result<OwnedValue> {
+    match value {
+        OwnedValue::Text(ref t) => {
+            // If X is a JSON value returned by another JSON function,
+            // then this function is a no-op
+            if t.subtype == TextSubtype::Json {
+                // Should just return the json value with no quotes
+                return Ok(value.to_owned());
+            }
+
+            let quoted_value = format!("\"{}\"", escape(&t.value));
+
+            Ok(OwnedValue::Text(LimboText::new(Rc::new(quoted_value))))
+        }
+        // Numbers are unquoted in json
+        OwnedValue::Integer(ref int) => Ok(OwnedValue::Integer(int.to_owned())),
+        OwnedValue::Float(ref float) => Ok(OwnedValue::Float(float.to_owned())),
+        OwnedValue::Blob(_) => crate::bail_constraint_error!("JSON cannot hold BLOB values"),
+        OwnedValue::Null => {
+            let null_value = "null".to_string();
+
+            Ok(OwnedValue::Text(LimboText::new(Rc::new(null_value))))
+        }
+        _ => {
+            // TODO not too sure what message should be here
+            crate::bail_parse_error!("Syntax error");
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

core/json/ser.rs

@@ -368,7 +368,11 @@ impl ser::SerializeStructVariant for &mut Serializer {
     }
 }
 
-fn escape(v: &str) -> String {
+// TODO not sure if this function can be public
+// But wanted to avoid having the same copy of the function in two different places
+// Maybe this function could be placed in mod file instead
+// As it is used by the json quote funcion
+pub fn escape(v: &str) -> String {
     v.chars()
         .flat_map(|c| match c {
             '"' => vec!['\\', c],

core/translate/expr.rs

@@ -899,6 +899,18 @@ pub fn translate_expr(
                     JsonFunc::JsonObject => {
                         let args = expect_arguments_even!(args, j);
 
+                        translate_function(
+                            program,
+                            &args,
+                            referenced_tables,
+                            resolver,
+                            target_register,
+                            func_ctx,
+                        )
+                    }
+                    JsonFunc::JsonQuote => {
+                        let args = expect_arguments_exact!(args, 1, j);
+
                         translate_function(
                             program,
                             &args,

core/vdbe/mod.rs

@@ -27,6 +27,7 @@ pub mod sorter;
 use crate::error::{LimboError, SQLITE_CONSTRAINT_PRIMARYKEY};
 use crate::ext::ExtValue;
 use crate::function::{AggFunc, ExtFunc, FuncCtx, MathFunc, MathFuncArity, ScalarFunc};
+use crate::json::json_quote;
 use crate::pseudo::PseudoCursor;
 use crate::result::LimboResult;
 use crate::storage::sqlite3_ondisk::DatabaseHeader;
@@ -1698,6 +1699,14 @@ impl Program {
                                     Err(e) => return Err(e),
                                 }
                             }
+                            JsonFunc::JsonQuote => {
+                                let json_value = &state.registers[*start_reg];
+                               
+                                match json_quote(json_value) {
+                                    Ok(result) => state.registers[*dest] = result,
+                                    Err(e) => return Err(e),
+                                }
+                            }
                         },
                         crate::function::Func::Scalar(scalar_func) => match scalar_func {
                             ScalarFunc::Cast => {

testing/json.test

@@ -544,3 +544,44 @@ do_execsql_test json_from_json_object {
 #do_execsql_test json_object_duplicated_keys {
 #    SELECT json_object('key', 'value', 'key', 'value2');
 #} {{{"key":"value2"}}}
+
+# The json_quote() function transforms an SQL value into a JSON value.
+# String values are quoted and interior quotes are escaped.  NULL values
+# are rendered as the unquoted string "null".
+#
+do_execsql_test json_quote_string_literal {
+  SELECT json_quote('abc"xyz');
+} {{"abc\"xyz"}}
+do_execsql_test json_quote_float {
+  SELECT json_quote(3.14159);
+} {3.14159}
+do_execsql_test json_quote_integer {
+  SELECT json_quote(12345);
+} {12345}
+do_execsql_test json_quote_null {
+  SELECT json_quote(null);
+} {"null"}
+do_execsql_test json_quote_null_caps {
+  SELECT json_quote(NULL);
+} null
+do_execsql_test json_quote_json_value {
+  SELECT json_quote(json('{a:1, b: "test"}'));
+} {{{"a":1,"b":"test"}}}
+
+
+# Escape character tests in sqlite source depend on json_valid
+# See https://github.com/sqlite/sqlite/blob/255548562b125e6c148bb27d49aaa01b2fe61dba/test/json102.test#L690
+# So for now not all control characters escaped are tested
+
+
+# TODO No catchsql tests function to test these on
+#do_catchsql_test json_quote_blob {
+#  SELECT json_quote(x'3031323334');
+#} {1 {JSON cannot hold BLOB values}}
+#do_catchsql_test json_quote_more_than_one_arg {
+#  SELECT json_quote(123,456)
+#} {1 {json_quote function called with not exactly 1 arguments}}
+#do_catchsql_test json_quote_no_args {
+#  SELECT json_quote()
+#} {1 {json_quote function with no arguments}}
+