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Merge pull request #1161 from derekdreery/debug_output
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Better output from `impl Debug for JsValue`.
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alexcrichton authored Jan 18, 2019
2 parents d3057c7 + f8680a0 commit ba732a8
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Showing 5 changed files with 147 additions and 26 deletions.
2 changes: 1 addition & 1 deletion .travis.yml
Original file line number Diff line number Diff line change
Expand Up @@ -6,7 +6,7 @@ INSTALL_NODE_VIA_NVM: &INSTALL_NODE_VIA_NVM
rustup target add wasm32-unknown-unknown
curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.33.8/install.sh | bash
source ~/.nvm/nvm.sh
nvm install v10.5
nvm install v10.9

INSTALL_GECKODRIVER: &INSTALL_GECKODRIVER
|
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82 changes: 82 additions & 0 deletions crates/cli-support/src/js/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -338,6 +338,88 @@ impl<'a> Context<'a> {
))
})?;

self.bind("__wbindgen_debug_string", &|me| {
me.expose_pass_string_to_wasm()?;
me.expose_get_object();
me.expose_uint32_memory();
Ok(String::from(
"
function(i, len_ptr) {
const toString = Object.prototype.toString;
const debug_str = val => {
// primitive types
const type = typeof val;
if (type == 'number' || type == 'boolean' || val == null) {
return `${val}`;
}
if (type == 'string') {
return `\"${val}\"`;
}
if (type == 'symbol') {
const description = val.description;
if (description == null) {
return 'Symbol';
} else {
return `Symbol(${description})`;
}
}
if (type == 'function') {
const name = val.name;
if (typeof name == 'string' && name.length > 0) {
return `Function(${name})`;
} else {
return 'Function';
}
}
// objects
if (Array.isArray(val)) {
const length = val.length;
let debug = '[';
if (length > 0) {
debug += debug_str(val[0]);
}
for(let i = 1; i < length; i++) {
debug += ', ' + debug_str(val[i]);
}
debug += ']';
return debug;
}
// Test for built-in
const builtInMatches = /\\[object ([^\\]]+)\\]/.exec(toString.call(val));
let className;
if (builtInMatches.length > 1) {
className = builtInMatches[1];
} else {
// Failed to match the standard '[object ClassName]'
return toString.call(val);
}
if (className == 'Object') {
// we're a user defined class or Object
// JSON.stringify avoids problems with cycles, and is generally much
// easier than looping through ownProperties of `val`.
try {
return 'Object(' + JSON.stringify(val) + ')';
} catch (_) {
return 'Object';
}
}
// errors
if (val instanceof Error) {
return `${val.name}: ${val.message}\n${val.stack}`;
}
// TODO we could test for more things here, like `Set`s and `Map`s.
return className;
};
const val = getObject(i);
const debug = debug_str(val);
const ptr = passStringToWasm(debug);
getUint32Memory()[len_ptr / 4] = WASM_VECTOR_LEN;
return ptr;
}
",
))
})?;

self.bind("__wbindgen_cb_drop", &|me| {
me.expose_drop_ref();
Ok(String::from(
Expand Down
47 changes: 25 additions & 22 deletions src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -303,6 +303,21 @@ impl JsValue {
pub fn is_function(&self) -> bool {
unsafe { __wbindgen_is_function(self.idx) == 1 }
}

/// Get a string representation of the JavaScript object for debugging
#[cfg(feature = "std")]
fn as_debug_string(&self) -> String {
unsafe {
let mut len = 0;
let ptr = __wbindgen_debug_string(self.idx, &mut len);
if ptr.is_null() {
unreachable!("`__wbindgen_debug_string` must return a valid string")
} else {
let data = Vec::from_raw_parts(ptr, len, len);
String::from_utf8_unchecked(data)
}
}
}
}

impl PartialEq for JsValue {
Expand Down Expand Up @@ -477,6 +492,7 @@ externs! {
fn __wbindgen_is_function(idx: u32) -> u32;
fn __wbindgen_is_string(idx: u32) -> u32;
fn __wbindgen_string_get(idx: u32, len: *mut usize) -> *mut u8;
fn __wbindgen_debug_string(idx: u32, len: *mut usize) -> *mut u8;
fn __wbindgen_throw(a: *const u8, b: usize) -> !;
fn __wbindgen_rethrow(a: u32) -> !;

Expand All @@ -503,30 +519,17 @@ impl Clone for JsValue {
}
}

#[cfg(feature = "std")]
impl fmt::Debug for JsValue {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
if let Some(n) = self.as_f64() {
return n.fmt(f);
}
#[cfg(feature = "std")]
{
if let Some(n) = self.as_string() {
return n.fmt(f);
}
}
if let Some(n) = self.as_bool() {
return n.fmt(f);
}
if self.is_null() {
return fmt::Display::fmt("null", f);
}
if self.is_undefined() {
return fmt::Display::fmt("undefined", f);
}
if self.is_symbol() {
return fmt::Display::fmt("Symbol(..)", f);
}
fmt::Display::fmt("[object]", f)
write!(f, "JsValue({})", self.as_debug_string())
}
}

#[cfg(not(feature = "std"))]
impl fmt::Debug for JsValue {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
f.write_str("JsValue")
}
}

Expand Down
14 changes: 14 additions & 0 deletions tests/wasm/api.js
Original file line number Diff line number Diff line change
Expand Up @@ -41,3 +41,17 @@ exports.js_eq_works = () => {
assert.strictEqual(wasm.eq_test(x, x), true);
assert.strictEqual(wasm.eq_test1(x), true);
};

exports.debug_values = () => ([
null,
undefined,
0,
1.0,
true,
[1,2,3],
"string",
{test: "object"},
[1.0, [2.0, 3.0]],
() => (null),
new Set(),
]);
28 changes: 25 additions & 3 deletions tests/wasm/api.rs
Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@ extern "C" {
fn js_works();
fn js_eq_works();
fn assert_null(v: JsValue);
fn debug_values() -> JsValue;
}

#[wasm_bindgen_test]
Expand Down Expand Up @@ -71,7 +72,7 @@ pub fn api_get_false() -> JsValue {
#[wasm_bindgen]
pub fn api_test_bool(a: &JsValue, b: &JsValue, c: &JsValue) {
assert_eq!(a.as_bool(), Some(true));
assert_eq!(format!("{:?}", a), "true");
assert_eq!(format!("{:?}", a), "JsValue(true)");
assert_eq!(b.as_bool(), Some(false));
assert_eq!(c.as_bool(), None);
}
Expand All @@ -80,7 +81,7 @@ pub fn api_test_bool(a: &JsValue, b: &JsValue, c: &JsValue) {
pub fn api_mk_symbol() -> JsValue {
let a = JsValue::symbol(None);
assert!(a.is_symbol());
assert_eq!(format!("{:?}", a), "Symbol(..)");
assert_eq!(format!("{:?}", a), "JsValue(Symbol)");
return a;
}

Expand All @@ -100,7 +101,7 @@ pub fn api_assert_symbols(a: &JsValue, b: &JsValue) {
#[wasm_bindgen]
pub fn api_acquire_string(a: &JsValue, b: &JsValue) {
assert_eq!(a.as_string().unwrap(), "foo");
assert_eq!(format!("{:?}", a), "\"foo\"");
assert_eq!(format!("{:?}", a), "JsValue(\"foo\")");
assert_eq!(b.as_string(), None);
}

Expand Down Expand Up @@ -145,3 +146,24 @@ fn memory_accessor_appears_to_work() {
.for_each(&mut |val, _, _| v.push(val));
assert_eq!(v, [3, 0, 0, 0]);
}

#[wasm_bindgen_test]
fn debug_output() {
let test_iter = debug_values().dyn_into::<js_sys::Array>().unwrap().values().into_iter();
let expecteds = vec![
"JsValue(null)",
"JsValue(undefined)",
"JsValue(0)",
"JsValue(1)",
"JsValue(true)",
"JsValue([1, 2, 3])",
"JsValue(\"string\")",
"JsValue(Object({\"test\":\"object\"}))",
"JsValue([1, [2, 3]])",
"JsValue(Function)",
"JsValue(Set)",
];
for (test, expected) in test_iter.zip(expecteds) {
assert_eq!(format!("{:?}", test.unwrap()), expected);
}
}

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