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refactor: json-stream-parser aligned to clippy standard

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Per Stark
2026-05-27 09:07:38 +02:00
parent 414d2f5b34
commit 18aadab8ee
3 changed files with 196 additions and 167 deletions
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Cargo.lock
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+1
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@@ -3533,6 +3533,7 @@ name = "json-stream-parser"
version = "0.1.0" version = "0.1.0"
dependencies = [ dependencies = [
"serde_json", "serde_json",
"thiserror 1.0.69",
] ]
[[package]] [[package]]
json-stream-parser/Cargo.toml
+1
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@@ -9,3 +9,4 @@ workspace = true
[dependencies] [dependencies]
serde_json = { workspace = true } serde_json = { workspace = true }
thiserror = { workspace = true }
json-stream-parser/src/lib.rs
+194 -167
View File
@@ -1,6 +1,7 @@
// This code is based on the json-stream-rust library (https://github.com/json-stream/json-stream-rust) // This code is based on the json-stream-rust library (https://github.com/json-stream/json-stream-rust)
// Original code is MIT licensed // Original code is MIT licensed
// Modified to fix escape character handling in strings // Modified to fix escape character handling in strings
use std::mem;
use serde_json::{json, Value}; use serde_json::{json, Value};
#[derive(Clone, Debug)] #[derive(Clone, Debug)]
@@ -9,107 +10,122 @@ enum ObjectStatus {
StringQuoteOpen(bool), StringQuoteOpen(bool),
StringQuoteClose, StringQuoteClose,
Scalar { Scalar {
value_so_far: Vec<char>, value_so_far: String,
}, },
ScalarNumber { ScalarNumber {
value_so_far: Vec<char>, value_so_far: String,
}, },
StartProperty, StartProperty,
KeyQuoteOpen { KeyQuoteOpen {
key_so_far: Vec<char>, key_so_far: String,
escaped: bool, escaped: bool,
}, },
KeyQuoteClose { KeyQuoteClose {
key: Vec<char>, key: String,
}, },
Colon { Colon {
key: Vec<char>, key: String,
}, },
ValueQuoteOpen { ValueQuoteOpen {
key: Vec<char>, key: String,
escaped: bool, escaped: bool,
}, },
ValueQuoteClose, ValueQuoteClose,
ValueScalar { ValueScalar {
key: Vec<char>, key: String,
value_so_far: Vec<char>, value_so_far: String,
}, },
Closed, Closed,
} }
/// Errors that can occur during streaming JSON parsing.
#[derive(Debug, thiserror::Error)]
pub enum ParseError {
/// A key that was expected to have a string value has a different type.
#[error("invalid value type for key `{0}`")]
InvalidValueType(String),
/// A numeric literal could not be parsed at the top level.
#[error("invalid number: {0}")]
InvalidNumber(String),
/// A scalar value inside an object could not be parsed as JSON.
#[error("invalid value for key `{0}`: {1}")]
InvalidObjectValue(String, String),
/// A character was encountered that does not fit the expected state.
#[error("unexpected character `{char}`")]
UnexpectedCharacter {
char: char,
},
}
fn add_char_into_object( fn add_char_into_object(
object: &mut Value, object: &mut Value,
current_status: &mut ObjectStatus, current_status: &mut ObjectStatus,
current_char: char, current_char: char,
) -> Result<(), String> { ) -> Result<(), ParseError> {
match (&*object, &*current_status, current_char) { match (&*object, &*current_status, current_char) {
// --- Top-level string value ---
(&Value::String(_), &ObjectStatus::StringQuoteOpen(true), '"') => { (&Value::String(_), &ObjectStatus::StringQuoteOpen(true), '"') => {
if let Value::String(str) = object { if let Value::String(s) = object {
str.push('"'); s.push('"');
}
if let ObjectStatus::StringQuoteOpen(ref mut escaped) = current_status {
*escaped = false;
} }
*current_status = ObjectStatus::StringQuoteOpen(false);
} }
(&Value::String(_), &ObjectStatus::StringQuoteOpen(false), '"') => { (&Value::String(_), &ObjectStatus::StringQuoteOpen(false), '"') => {
*current_status = ObjectStatus::StringQuoteClose; *current_status = ObjectStatus::StringQuoteClose;
} }
(&Value::String(_), &ObjectStatus::StringQuoteOpen(true), c) => { (&Value::String(_), &ObjectStatus::StringQuoteOpen(true), c) => {
if let Value::String(str) = object { if let Value::String(s) = object {
str.push('\\'); s.push('\\');
str.push(c); s.push(c);
}
if let ObjectStatus::StringQuoteOpen(ref mut escaped) = current_status {
*escaped = false;
} }
*current_status = ObjectStatus::StringQuoteOpen(false);
} }
(&Value::String(_), &ObjectStatus::StringQuoteOpen(false), '\\') => { (&Value::String(_), &ObjectStatus::StringQuoteOpen(false), '\\') => {
*current_status = ObjectStatus::StringQuoteOpen(true); if let ObjectStatus::StringQuoteOpen(ref mut escaped) = current_status {
*escaped = true;
}
} }
(&Value::String(_), &ObjectStatus::StringQuoteOpen(false), c) => { (&Value::String(_), &ObjectStatus::StringQuoteOpen(false), c) => {
if let Value::String(str) = object { if let Value::String(s) = object {
str.push(c); s.push(c);
} }
} }
// --- Object: key with escaped quote ---
(&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: true, .. }, '"') => { (&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: true, .. }, '"') => {
if let ObjectStatus::KeyQuoteOpen { if let ObjectStatus::KeyQuoteOpen { ref mut key_so_far, ref mut escaped } =
ref mut key_so_far, .. current_status
} = current_status
{ {
key_so_far.push('"'); key_so_far.push('"');
*current_status = ObjectStatus::KeyQuoteOpen { *escaped = false;
key_so_far: key_so_far.clone(),
escaped: false,
};
} }
} }
(&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: false, .. }, '"') => { (&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: false, .. }, '"') => {
if let ObjectStatus::KeyQuoteOpen { ref key_so_far, .. } = current_status { if let ObjectStatus::KeyQuoteOpen { ref mut key_so_far, .. } = current_status {
let key = key_so_far.iter().collect::<String>(); let key = mem::take(key_so_far);
if let Value::Object(obj) = object { if let Value::Object(obj) = object {
obj.insert(key, Value::Null); obj.insert(key.clone(), Value::Null);
} }
*current_status = ObjectStatus::KeyQuoteClose { *current_status = ObjectStatus::KeyQuoteClose { key };
key: key_so_far.clone(),
};
} }
} }
// --- Object: key with escaped other char ---
(&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: true, .. }, c) => { (&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: true, .. }, c) => {
if let ObjectStatus::KeyQuoteOpen { if let ObjectStatus::KeyQuoteOpen { ref mut key_so_far, ref mut escaped } =
ref mut key_so_far, .. current_status
} = current_status
{ {
key_so_far.push('\\'); key_so_far.push('\\');
key_so_far.push(c); key_so_far.push(c);
*current_status = ObjectStatus::KeyQuoteOpen { *escaped = false;
key_so_far: key_so_far.clone(),
escaped: false,
};
} }
} }
(&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: false, .. }, '\\') => { (&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: false, .. }, '\\') => {
if let ObjectStatus::KeyQuoteOpen { ref key_so_far, .. } = current_status { if let ObjectStatus::KeyQuoteOpen { ref mut escaped, .. } = current_status {
*current_status = ObjectStatus::KeyQuoteOpen { *escaped = true;
key_so_far: key_so_far.clone(),
escaped: true,
};
} }
} }
(&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: false, .. }, c) => { (&Value::Object(_), &ObjectStatus::KeyQuoteOpen { escaped: false, .. }, c) => {
@@ -121,59 +137,49 @@ fn add_char_into_object(
} }
} }
// --- Object: value with escaped quote ---
(&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: true, .. }, '"') => { (&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: true, .. }, '"') => {
if let ObjectStatus::ValueQuoteOpen { ref key, .. } = current_status { if let ObjectStatus::ValueQuoteOpen { ref key, ref mut escaped } = current_status {
let key_str = key.iter().collect::<String>();
if let Value::Object(obj) = object { if let Value::Object(obj) = object {
if let Some(Value::String(value)) = obj.get_mut(&key_str) { if let Some(Value::String(value)) = obj.get_mut(key) {
value.push('"'); value.push('"');
} }
} }
*current_status = ObjectStatus::ValueQuoteOpen { *escaped = false;
key: key.clone(),
escaped: false,
};
} }
} }
(&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: false, .. }, '"') => { (&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: false, .. }, '"') => {
*current_status = ObjectStatus::ValueQuoteClose; *current_status = ObjectStatus::ValueQuoteClose;
} }
(&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: true, .. }, c) => { (&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: true, .. }, c) => {
if let ObjectStatus::ValueQuoteOpen { ref key, .. } = current_status { if let ObjectStatus::ValueQuoteOpen { ref key, ref mut escaped } = current_status {
let key_str = key.iter().collect::<String>();
if let Value::Object(obj) = object { if let Value::Object(obj) = object {
if let Some(Value::String(value)) = obj.get_mut(&key_str) { if let Some(Value::String(value)) = obj.get_mut(key) {
value.push('\\'); value.push('\\');
value.push(c); value.push(c);
} }
} }
*current_status = ObjectStatus::ValueQuoteOpen { *escaped = false;
key: key.clone(),
escaped: false,
};
} }
} }
(&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: false, .. }, '\\') => { (&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: false, .. }, '\\') => {
if let ObjectStatus::ValueQuoteOpen { ref key, .. } = current_status { if let ObjectStatus::ValueQuoteOpen { ref mut escaped, .. } = current_status {
*current_status = ObjectStatus::ValueQuoteOpen { *escaped = true;
key: key.clone(),
escaped: true,
};
} }
} }
(&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: false, .. }, c) => { (&Value::Object(_), &ObjectStatus::ValueQuoteOpen { escaped: false, .. }, c) => {
if let ObjectStatus::ValueQuoteOpen { ref key, .. } = current_status { if let ObjectStatus::ValueQuoteOpen { ref key, .. } = current_status {
let key_str = key.iter().collect::<String>();
if let Value::Object(obj) = object { if let Value::Object(obj) = object {
if let Some(Value::String(value)) = obj.get_mut(&key_str) { if let Some(Value::String(value)) = obj.get_mut(key) {
value.push(c); value.push(c);
} else { } else {
return Err(format!("Invalid value type for key {}", key_str)); return Err(ParseError::InvalidValueType(key.clone()));
} }
} }
} }
} }
// --- Top-level init ---
(&Value::Null, &ObjectStatus::Ready, '"') => { (&Value::Null, &ObjectStatus::Ready, '"') => {
*object = json!(""); *object = json!("");
*current_status = ObjectStatus::StringQuoteOpen(false); *current_status = ObjectStatus::StringQuoteOpen(false);
@@ -186,7 +192,7 @@ fn add_char_into_object(
(&Value::Null, &ObjectStatus::Ready, 't') => { (&Value::Null, &ObjectStatus::Ready, 't') => {
*object = json!(true); *object = json!(true);
*current_status = ObjectStatus::Scalar { *current_status = ObjectStatus::Scalar {
value_so_far: vec!['t'], value_so_far: "t".into(),
}; };
} }
(&Value::Bool(true), &ObjectStatus::Scalar { .. }, 'r') => { (&Value::Bool(true), &ObjectStatus::Scalar { .. }, 'r') => {
@@ -194,7 +200,7 @@ fn add_char_into_object(
ref mut value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
if *value_so_far == vec!['t'] { if *value_so_far == "t" {
value_so_far.push('r'); value_so_far.push('r');
} }
} }
@@ -204,19 +210,21 @@ fn add_char_into_object(
ref mut value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
if *value_so_far == vec!['t', 'r'] { if *value_so_far == "tr" {
value_so_far.push('u'); value_so_far.push('u');
} }
} }
} }
(&Value::Bool(true), &ObjectStatus::Scalar { .. }, 'e') => { (&Value::Bool(true), &ObjectStatus::Scalar { .. }, 'e')
| (&Value::Bool(false), &ObjectStatus::Scalar { .. }, 'e')
| (&Value::Object(_), &ObjectStatus::ValueQuoteClose, '}') => {
*current_status = ObjectStatus::Closed; *current_status = ObjectStatus::Closed;
} }
(&Value::Null, &ObjectStatus::Ready, 'f') => { (&Value::Null, &ObjectStatus::Ready, 'f') => {
*object = json!(false); *object = json!(false);
*current_status = ObjectStatus::Scalar { *current_status = ObjectStatus::Scalar {
value_so_far: vec!['f'], value_so_far: "f".into(),
}; };
} }
(&Value::Bool(false), &ObjectStatus::Scalar { .. }, 'a') => { (&Value::Bool(false), &ObjectStatus::Scalar { .. }, 'a') => {
@@ -224,7 +232,7 @@ fn add_char_into_object(
ref mut value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
if *value_so_far == vec!['f'] { if *value_so_far == "f" {
value_so_far.push('a'); value_so_far.push('a');
} }
} }
@@ -234,7 +242,7 @@ fn add_char_into_object(
ref mut value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
if *value_so_far == vec!['f', 'a'] { if *value_so_far == "fa" {
value_so_far.push('l'); value_so_far.push('l');
} }
} }
@@ -244,19 +252,16 @@ fn add_char_into_object(
ref mut value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
if *value_so_far == vec!['f', 'a', 'l'] { if *value_so_far == "fal" {
value_so_far.push('s'); value_so_far.push('s');
} }
} }
} }
(&Value::Bool(false), &ObjectStatus::Scalar { .. }, 'e') => {
*current_status = ObjectStatus::Closed;
}
(&Value::Null, &ObjectStatus::Ready, 'n') => { (&Value::Null, &ObjectStatus::Ready, 'n') => {
*object = json!(null); *object = json!(null);
*current_status = ObjectStatus::Scalar { *current_status = ObjectStatus::Scalar {
value_so_far: vec!['n'], value_so_far: "n".into(),
}; };
} }
(&Value::Null, &ObjectStatus::Scalar { .. }, 'u') => { (&Value::Null, &ObjectStatus::Scalar { .. }, 'u') => {
@@ -264,7 +269,7 @@ fn add_char_into_object(
ref mut value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
if *value_so_far == vec!['n'] { if *value_so_far == "n" {
value_so_far.push('u'); value_so_far.push('u');
} }
} }
@@ -274,24 +279,27 @@ fn add_char_into_object(
ref mut value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
if *value_so_far == vec!['n', 'u'] { if *value_so_far == "nu" {
value_so_far.push('l'); value_so_far.push('l');
} else if *value_so_far == vec!['n', 'u', 'l'] { } else if *value_so_far == "nul" {
*current_status = ObjectStatus::Closed; *current_status = ObjectStatus::Closed;
} }
} }
} }
// --- Numbers ---
(&Value::Null, &ObjectStatus::Ready, c @ '0'..='9') => { (&Value::Null, &ObjectStatus::Ready, c @ '0'..='9') => {
*object = Value::Number(c.to_digit(10).unwrap().into()); if let Some(digit) = c.to_digit(10) {
*object = Value::Number(digit.into());
}
*current_status = ObjectStatus::ScalarNumber { *current_status = ObjectStatus::ScalarNumber {
value_so_far: vec![c], value_so_far: c.to_string(),
}; };
} }
(&Value::Null, &ObjectStatus::Ready, '-') => { (&Value::Null, &ObjectStatus::Ready, '-') => {
*object = Value::Number(0.into()); *object = Value::Number(0.into());
*current_status = ObjectStatus::ScalarNumber { *current_status = ObjectStatus::ScalarNumber {
value_so_far: vec!['-'], value_so_far: "-".into(),
}; };
} }
(&Value::Number(_), &ObjectStatus::ScalarNumber { .. }, c @ '0'..='9') => { (&Value::Number(_), &ObjectStatus::ScalarNumber { .. }, c @ '0'..='9') => {
@@ -301,22 +309,22 @@ fn add_char_into_object(
{ {
value_so_far.push(c); value_so_far.push(c);
if let Value::Number(ref mut num) = object { if let Value::Number(ref mut num) = object {
if value_so_far.contains(&'.') { if value_so_far.contains('.') {
let parsed_number = value_so_far let parsed: f64 = value_so_far.parse().map_err(|e| {
.iter() ParseError::InvalidNumber(format!(
.collect::<String>() "invalid float: `{value_so_far}` ({e})"
.parse::<f64>() ))
.unwrap(); })?;
if let Some(json_number) = serde_json::Number::from_f64(parsed_number) { if let Some(json_number) = serde_json::Number::from_f64(parsed) {
*num = json_number; *num = json_number;
} }
} else { } else {
let parsed_number = value_so_far let parsed: i64 = value_so_far.parse().map_err(|e| {
.iter() ParseError::InvalidNumber(format!(
.collect::<String>() "invalid integer: `{value_so_far}` ({e})"
.parse::<i64>() ))
.unwrap(); })?;
*num = parsed_number.into(); *num = parsed.into();
} }
} }
} }
@@ -330,53 +338,58 @@ fn add_char_into_object(
} }
} }
// --- Object structure ---
(&Value::Object(_), &ObjectStatus::StartProperty, '"') => { (&Value::Object(_), &ObjectStatus::StartProperty, '"') => {
*current_status = ObjectStatus::KeyQuoteOpen { *current_status = ObjectStatus::KeyQuoteOpen {
key_so_far: vec![], key_so_far: String::new(),
escaped: false, escaped: false,
}; };
} }
(&Value::Object(_), &ObjectStatus::KeyQuoteClose { .. }, ':') => { (&Value::Object(_), &ObjectStatus::KeyQuoteClose { .. }, ':') => {
if let ObjectStatus::KeyQuoteClose { ref key } = current_status { if let ObjectStatus::KeyQuoteClose { ref mut key } = current_status {
*current_status = ObjectStatus::Colon { key: key.clone() }; let key = mem::take(key);
*current_status = ObjectStatus::Colon { key };
} }
} }
(&Value::Object(_), &ObjectStatus::Colon { .. }, ' ' | '\n') => {} (&Value::Object(_), &ObjectStatus::Colon { .. }, ' ' | '\n' | '\t' | '\r') => {}
(&Value::Object(_), &ObjectStatus::Colon { .. }, '"') => { (&Value::Object(_), &ObjectStatus::Colon { .. }, '"') => {
if let ObjectStatus::Colon { ref key } = current_status { if let ObjectStatus::Colon { ref mut key } = current_status {
let key_str = key.iter().collect::<String>(); let key_str = mem::take(key);
if let Value::Object(obj) = object { if let Value::Object(obj) = object {
obj.insert(key_str, json!("")); obj.insert(key_str.clone(), json!(""));
} }
*current_status = ObjectStatus::ValueQuoteOpen { *current_status = ObjectStatus::ValueQuoteOpen {
key: key.clone(), key: key_str,
escaped: false, escaped: false,
}; };
} }
} }
(&Value::Object(_), &ObjectStatus::Colon { .. }, char) => { (&Value::Object(_), &ObjectStatus::Colon { .. }, char) => {
if let ObjectStatus::Colon { ref key } = current_status { if let ObjectStatus::Colon { ref mut key } = current_status {
let key = mem::take(key);
*current_status = ObjectStatus::ValueScalar { *current_status = ObjectStatus::ValueScalar {
key: key.clone(), key,
value_so_far: vec![char], value_so_far: char.to_string(),
}; };
} }
} }
(&Value::Object(_), &ObjectStatus::ValueScalar { .. }, ',') => { (&Value::Object(_), &ObjectStatus::ValueScalar { .. }, ',') => {
if let ObjectStatus::ValueScalar { if let ObjectStatus::ValueScalar {
ref key, ref mut key,
ref value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
let key_str = key.iter().collect::<String>(); let key = mem::take(key);
let value_str = value_so_far.iter().collect::<String>(); let value_str = mem::take(value_so_far);
if let Value::Object(obj) = object { if let Value::Object(obj) = object {
match value_str.parse::<Value>() { match value_str.parse::<Value>() {
Ok(value) => { Ok(value) => {
obj.insert(key_str, value); obj.insert(key, value);
}
Err(e) => {
return Err(ParseError::InvalidObjectValue(key, e.to_string()));
} }
Err(e) => return Err(format!("Invalid value for key {}: {}", key_str, e)),
} }
} }
*current_status = ObjectStatus::StartProperty; *current_status = ObjectStatus::StartProperty;
@@ -384,18 +397,20 @@ fn add_char_into_object(
} }
(&Value::Object(_), &ObjectStatus::ValueScalar { .. }, '}') => { (&Value::Object(_), &ObjectStatus::ValueScalar { .. }, '}') => {
if let ObjectStatus::ValueScalar { if let ObjectStatus::ValueScalar {
ref key, ref mut key,
ref value_so_far, ref mut value_so_far,
} = current_status } = current_status
{ {
let key_str = key.iter().collect::<String>(); let key = mem::take(key);
let value_str = value_so_far.iter().collect::<String>(); let value_str = mem::take(value_so_far);
if let Value::Object(obj) = object { if let Value::Object(obj) = object {
match value_str.parse::<Value>() { match value_str.parse::<Value>() {
Ok(value) => { Ok(value) => {
obj.insert(key_str, value); obj.insert(key, value);
}
Err(e) => {
return Err(ParseError::InvalidObjectValue(key, e.to_string()));
} }
Err(e) => return Err(format!("Invalid value for key {}: {}", key_str, e)),
} }
} }
*current_status = ObjectStatus::Closed; *current_status = ObjectStatus::Closed;
@@ -414,54 +429,54 @@ fn add_char_into_object(
(&Value::Object(_), &ObjectStatus::ValueQuoteClose, ',') => { (&Value::Object(_), &ObjectStatus::ValueQuoteClose, ',') => {
*current_status = ObjectStatus::StartProperty; *current_status = ObjectStatus::StartProperty;
} }
(&Value::Object(_), &ObjectStatus::ValueQuoteClose, '}') => { (_, _, ' ' | '\n' | '\t' | '\r') => {}
*current_status = ObjectStatus::Closed;
}
(_, _, ' ' | '\n') => {} (_, _, c) => {
return Err(ParseError::UnexpectedCharacter { char: c });
(val, st, c) => {
return Err(format!(
"Invalid character {} status: {:?} value: {:?}",
c, st, val
));
} }
} }
Ok(()) Ok(())
} }
#[cfg(debug_assertions)] /// Parse a complete JSON string in one shot.
pub fn parse_stream(json_string: &str) -> Result<Value, String> { ///
/// Processes the input character-by-character through the streaming parser state machine.
///
/// # Errors
///
/// Returns [`ParseError`] if the input contains invalid JSON or unexpected characters
/// for the current parser state.
#[must_use]
pub fn parse_stream(json_string: &str) -> Result<Value, ParseError> {
let mut out: Value = Value::Null; let mut out: Value = Value::Null;
let mut current_status = ObjectStatus::Ready; let mut current_status = ObjectStatus::Ready;
for current_char in json_string.chars() { for current_char in json_string.chars() {
println!( add_char_into_object(&mut out, &mut current_status, current_char)?;
"variables: {:?} {:?} {:?}",
out,
current_status.clone(),
current_char.to_string()
);
add_char_into_object(&mut out, &mut current_status, current_char)?
} }
Ok(out) Ok(out)
} }
#[cfg(not(debug_assertions))] /// An incremental streaming JSON parser that processes one character at a time.
pub fn parse_stream(json_string: &str) -> Result<Value, String> { ///
let mut out: Value = Value::Null; /// Create via [`JsonStreamParser::new()`], feed characters with [`add_char`](Self::add_char),
let mut current_status = ObjectStatus::Ready; /// and retrieve the result with [`result`](Self::result).
for current_char in json_string.chars() { ///
if let Err(e) = add_char_into_object(&mut out, &mut current_status, current_char) { /// # Example
return Err(e); ///
} /// ```
} /// # use json_stream_parser::JsonStreamParser;
return Ok(out); /// let mut parser = JsonStreamParser::new();
} /// for c in r#"{"key": "value"}"#.chars() {
/// parser.add_char(c).unwrap();
/// }
/// let result = parser.result();
/// ```
#[derive(Debug)]
pub struct JsonStreamParser { pub struct JsonStreamParser {
object: Value, object: Value,
current_status: ObjectStatus, current_status: ObjectStatus,
} }
impl Default for JsonStreamParser { impl Default for JsonStreamParser {
fn default() -> Self { fn default() -> Self {
Self::new() Self::new()
@@ -469,16 +484,27 @@ impl Default for JsonStreamParser {
} }
impl JsonStreamParser { impl JsonStreamParser {
/// Create a new streaming parser in the initial state.
#[must_use]
pub fn new() -> JsonStreamParser { pub fn new() -> JsonStreamParser {
JsonStreamParser { JsonStreamParser {
object: Value::Null, object: Value::Null,
current_status: ObjectStatus::Ready, current_status: ObjectStatus::Ready,
} }
} }
pub fn add_char(&mut self, current_char: char) -> Result<(), String> {
/// Feed one character into the parser.
///
/// # Errors
///
/// Returns [`ParseError`] if the character is invalid for the current state.
pub fn add_char(&mut self, current_char: char) -> Result<(), ParseError> {
add_char_into_object(&mut self.object, &mut self.current_status, current_char) add_char_into_object(&mut self.object, &mut self.current_status, current_char)
} }
pub fn get_result(&self) -> &Value {
/// Borrow the current parsed value.
#[must_use]
pub fn result(&self) -> &Value {
&self.object &self.object
} }
} }
@@ -487,6 +513,7 @@ macro_rules! param_test {
($($name:ident: $string:expr, $value:expr)*) => { ($($name:ident: $string:expr, $value:expr)*) => {
$( $(
mod $name { mod $name {
#![allow(clippy::unwrap_used, clippy::unreadable_literal)]
#[allow(unused_imports)] #[allow(unused_imports)]
use super::{parse_stream, JsonStreamParser}; use super::{parse_stream, JsonStreamParser};
#[allow(unused_imports)] #[allow(unused_imports)]
@@ -496,13 +523,13 @@ macro_rules! param_test {
fn simple() { fn simple() {
let string: &str = $string; let string: &str = $string;
let value: Value = $value; let value: Value = $value;
let result = parse_stream(&string); let result = parse_stream(string);
assert_eq!(result.unwrap(), value); assert_eq!(result.unwrap(), value);
let mut parser = JsonStreamParser::new(); let mut parser = JsonStreamParser::new();
for c in string.chars() { for c in string.chars() {
parser.add_char(c).unwrap(); parser.add_char(c).unwrap();
} }
assert_eq!(parser.get_result(), &value); assert_eq!(parser.result(), &value);
} }
#[test] #[test]
@@ -517,7 +544,7 @@ macro_rules! param_test {
for c in raw_json.chars() { for c in raw_json.chars() {
parser.add_char(c).unwrap(); parser.add_char(c).unwrap();
} }
assert_eq!(parser.get_result(), &expected); assert_eq!(parser.result(), &expected);
} }
#[test] #[test]
@@ -532,7 +559,7 @@ macro_rules! param_test {
for c in raw_json.chars() { for c in raw_json.chars() {
parser.add_char(c).unwrap(); parser.add_char(c).unwrap();
} }
assert_eq!(parser.get_result(), &expected); assert_eq!(parser.result(), &expected);
} }
#[test] #[test]
@@ -547,7 +574,7 @@ macro_rules! param_test {
for c in raw_json.chars() { for c in raw_json.chars() {
parser.add_char(c).unwrap(); parser.add_char(c).unwrap();
} }
assert_eq!(parser.get_result(), &expected); assert_eq!(parser.result(), &expected);
} }
#[test] #[test]
@@ -562,7 +589,7 @@ macro_rules! param_test {
for c in raw_json.chars() { for c in raw_json.chars() {
parser.add_char(c).unwrap(); parser.add_char(c).unwrap();
} }
assert_eq!(parser.get_result(), &expected); assert_eq!(parser.result(), &expected);
} }
#[test] #[test]
@@ -580,7 +607,7 @@ macro_rules! param_test {
for c in raw_json.chars() { for c in raw_json.chars() {
parser.add_char(c).unwrap(); parser.add_char(c).unwrap();
} }
assert_eq!(parser.get_result(), &expected); assert_eq!(parser.result(), &expected);
} }
#[test] #[test]
@@ -596,7 +623,7 @@ macro_rules! param_test {
for c in raw_json.chars() { for c in raw_json.chars() {
assert!(parser.add_char(c).is_ok(), "Add char error"); assert!(parser.add_char(c).is_ok(), "Add char error");
} }
assert_eq!(parser.get_result(), &expected); assert_eq!(parser.result(), &expected);
} }
} }
)* )*
@@ -607,18 +634,18 @@ param_test! {
null: r#"null"#, Value::Null null: r#"null"#, Value::Null
true_value: r#"true"#, Value::Bool(true) true_value: r#"true"#, Value::Bool(true)
false_value: r#"false"#, Value::Bool(false) false_value: r#"false"#, Value::Bool(false)
empty_string: r#""""#, Value::String("".to_string()) empty_string: r#""""#, Value::String(String::new())
single_character_string: r#""a""#, Value::String("a".to_string()) single_character_string: r#""a""#, Value::String("a".to_string())
string_with_spaces: r#""a b c""#, Value::String("a b c".to_string()) string_with_spaces: r#""a b c""#, Value::String("a b c".to_string())
string_with_space_at_end: r#""a b c ""#, Value::String("a b c ".to_string()) string_with_space_at_end: r#""a b c ""#, Value::String("a b c ".to_string())
string_with_space_at_start: r#"" a b c""#, Value::String(" a b c".to_string()) string_with_space_at_start: r#"" a b c""#, Value::String(" a b c".to_string())
string_with_space_at_start_and_end: r#"" a b c ""#, Value::String(" a b c ".to_string()) string_with_space_at_start_and_end: r#"" a b c ""#, Value::String(" a b c ".to_string())
number: r#"1234567890"#, Value::Number(1234567890.into()) number: r#"1234567890"#, Value::Number(1_234_567_890.into())
single_digit_number: r#"1"#, Value::Number(1.into()) single_digit_number: r#"1"#, Value::Number(1.into())
number_with_spaces_at_start: r#" 1234567890"#, Value::Number(1234567890.into()) number_with_spaces_at_start: r#" 1234567890"#, Value::Number(1_234_567_890.into())
number_with_spaces_at_end: r#"1234567890 "#, Value::Number(1234567890.into()) number_with_spaces_at_end: r#"1234567890 "#, Value::Number(1_234_567_890.into())
number_with_spaces_at_start_and_end: r#" 1234567890 "#, Value::Number(1234567890.into()) number_with_spaces_at_start_and_end: r#" 1234567890 "#, Value::Number(1_234_567_890.into())
negative_number: r#"-1234567890"#, Value::Number((-1234567890).into()) negative_number: r#"-1234567890"#, Value::Number((-1_234_567_890i64).into())
negative_single_digit_number: r#"-1"#, Value::Number((-1).into()) negative_single_digit_number: r#"-1"#, Value::Number((-1).into())
zero: r#"0"#, Value::Number(0.into()) zero: r#"0"#, Value::Number(0.into())
float: r#"123.456"#, Value::Number(serde_json::Number::from_f64(123.456).unwrap()) float: r#"123.456"#, Value::Number(serde_json::Number::from_f64(123.456).unwrap())