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128 lines
3.9 KiB
Rust
128 lines
3.9 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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//! Supports writing a trace file created during each layout scope
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//! that can be viewed by an external tool to make layout debugging easier.
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#![macro_escape]
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use flow_ref::FlowRef;
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use flow;
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use serialize::json;
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use std::cell::RefCell;
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use std::io::File;
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use std::sync::atomic::{AtomicUint, SeqCst, INIT_ATOMIC_UINT};
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thread_local!(static STATE_KEY: RefCell<Option<State>> = RefCell::new(None))
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static mut DEBUG_ID_COUNTER: AtomicUint = INIT_ATOMIC_UINT;
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pub struct Scope;
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#[macro_export]
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macro_rules! layout_debug_scope(
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($($arg:tt)*) => (
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if cfg!(not(ndebug)) {
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layout_debug::Scope::new(format!($($arg)*))
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} else {
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layout_debug::Scope
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}
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)
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)
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#[deriving(Encodable)]
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struct ScopeData {
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name: String,
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pre: String,
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post: String,
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children: Vec<Box<ScopeData>>,
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}
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impl ScopeData {
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fn new(name: String, pre: String) -> ScopeData {
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ScopeData {
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name: name,
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pre: pre,
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post: String::new(),
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children: vec!(),
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}
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}
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}
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struct State {
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flow_root: FlowRef,
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scope_stack: Vec<Box<ScopeData>>,
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}
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/// A layout debugging scope. The entire state of the flow tree
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/// will be output at the beginning and end of this scope.
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impl Scope {
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pub fn new(name: String) -> Scope {
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STATE_KEY.with(|ref r| {
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match &mut *r.borrow_mut() {
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&Some(ref mut state) => {
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let flow_trace = json::encode(&flow::base(state.flow_root.deref()));
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let data = box ScopeData::new(name.clone(), flow_trace);
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state.scope_stack.push(data);
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}
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&None => {}
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}
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});
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Scope
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}
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}
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#[cfg(not(ndebug))]
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impl Drop for Scope {
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fn drop(&mut self) {
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STATE_KEY.with(|ref r| {
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match &mut *r.borrow_mut() {
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&Some(ref mut state) => {
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let mut current_scope = state.scope_stack.pop().unwrap();
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current_scope.post = json::encode(&flow::base(state.flow_root.deref()));
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let previous_scope = state.scope_stack.last_mut().unwrap();
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previous_scope.children.push(current_scope);
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}
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&None => {}
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}
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});
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}
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}
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/// Generate a unique ID. This is used for items such as Fragment
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/// which are often reallocated but represent essentially the
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/// same data.
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pub fn generate_unique_debug_id() -> u16 {
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unsafe { DEBUG_ID_COUNTER.fetch_add(1, SeqCst) as u16 }
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}
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/// Begin a layout debug trace. If this has not been called,
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/// creating debug scopes has no effect.
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pub fn begin_trace(flow_root: FlowRef) {
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assert!(STATE_KEY.with(|ref r| r.borrow().is_none()));
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STATE_KEY.with(|ref r| {
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let flow_trace = json::encode(&flow::base(flow_root.deref()));
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let state = State {
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scope_stack: vec![box ScopeData::new("root".into_string(), flow_trace)],
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flow_root: flow_root.clone(),
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};
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*r.borrow_mut() = Some(state);
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});
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}
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/// End the debug layout trace. This will write the layout
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/// trace to disk in the current directory. The output
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/// file can then be viewed with an external tool.
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pub fn end_trace() {
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let mut task_state = STATE_KEY.with(|ref r| r.borrow_mut().take().unwrap());
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assert!(task_state.scope_stack.len() == 1);
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let mut root_scope = task_state.scope_stack.pop().unwrap();
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root_scope.post = json::encode(&flow::base(task_state.flow_root.deref()));
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let result = json::encode(&root_scope);
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let path = Path::new("layout_trace.json");
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let mut file = File::create(&path).unwrap();
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file.write_str(result.as_slice()).unwrap();
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}
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