chore: simplify dependency tracking

pull/12077/head
Rich Harris 5 months ago
parent 90ce1d5f0b
commit 8c7826875a

@ -93,7 +93,7 @@ export function set_current_effect(effect) {
/** @type {null | import('#client').Value[]} */
export let current_dependencies = null;
let current_dependencies_index = 0;
/**
* Tracks writes that the effect it's executed in doesn't listen to yet,
* so that the dependency can be added to the effect later on if it then reads it
@ -334,88 +334,61 @@ function handle_error(error, effect, component_context) {
/**
* @template V
* @param {import('#client').Reaction} signal
* @param {import('#client').Reaction} reaction
* @returns {V}
*/
export function execute_reaction_fn(signal) {
export function execute_reaction_fn(reaction) {
const previous_dependencies = current_dependencies;
const previous_dependencies_index = current_dependencies_index;
const previous_untracked_writes = current_untracked_writes;
const previous_reaction = current_reaction;
const previous_skip_reaction = current_skip_reaction;
current_dependencies = /** @type {null | import('#client').Value[]} */ (null);
current_dependencies_index = 0;
current_untracked_writes = null;
current_reaction = (signal.f & (BRANCH_EFFECT | ROOT_EFFECT)) === 0 ? signal : null;
current_skip_reaction = !is_flushing_effect && (signal.f & UNOWNED) !== 0;
current_reaction = (reaction.f & (BRANCH_EFFECT | ROOT_EFFECT)) === 0 ? reaction : null;
current_skip_reaction = !is_flushing_effect && (reaction.f & UNOWNED) !== 0;
try {
let res = /** @type {Function} */ (0, signal.fn)();
let dependencies = /** @type {import('#client').Value<unknown>[]} **/ (signal.deps);
if (current_dependencies !== null) {
let i;
if (dependencies !== null) {
const deps_length = dependencies.length;
// Include any dependencies up until the current_dependencies_index.
const full_current_dependencies =
current_dependencies_index === 0
? current_dependencies
: dependencies.slice(0, current_dependencies_index).concat(current_dependencies);
const current_dep_length = full_current_dependencies.length;
// If we have more than 16 elements in the array then use a Set for faster performance
// TODO: evaluate if we should always just use a Set or not here?
const full_current_dependencies_set =
current_dep_length > 16 && deps_length - current_dependencies_index > 1
? new Set(full_current_dependencies)
: null;
for (i = current_dependencies_index; i < deps_length; i++) {
const dependency = dependencies[i];
if (
full_current_dependencies_set !== null
? !full_current_dependencies_set.has(dependency)
: !full_current_dependencies.includes(dependency)
) {
remove_reaction(signal, dependency);
}
let result = /** @type {Function} */ (0, reaction.fn)();
let old_deps = reaction.deps;
var start = 0;
var i;
var dependency;
// very often, dependencies stay the same between runs — optimise for that case
// by skipping the first n identical dependencies
if (current_dependencies !== null && old_deps !== null) {
var min = Math.min(current_dependencies.length, old_deps.length);
for (; start < min; start += 1) {
if (current_dependencies[start] !== old_deps[start]) break;
}
}
if (dependencies !== null && current_dependencies_index > 0) {
dependencies.length = current_dependencies_index + current_dependencies.length;
for (i = 0; i < current_dependencies.length; i++) {
dependencies[current_dependencies_index + i] = current_dependencies[i];
if (old_deps !== null) {
for (i = start; i < old_deps.length; i += 1) {
dependency = old_deps[i];
if (current_dependencies === null || !current_dependencies.includes(dependency)) {
remove_reaction(reaction, dependency);
}
} else {
signal.deps = /** @type {import('#client').Value<V>[]} **/ (
dependencies = current_dependencies
);
}
if (!current_skip_reaction) {
for (i = current_dependencies_index; i < dependencies.length; i++) {
const dependency = dependencies[i];
const reactions = dependency.reactions;
if (reactions === null) {
dependency.reactions = [signal];
} else if (reactions[reactions.length - 1] !== signal) {
// TODO: should this be:
//
// } else if (!reactions.includes(signal)) {
//
reactions.push(signal);
}
if (current_dependencies !== null && !current_skip_reaction) {
for (i = start; i < current_dependencies.length; i += 1) {
dependency = current_dependencies[i];
if (old_deps === null || !old_deps.includes(dependency)) {
(dependency.reactions ??= []).push(reaction);
}
}
} else if (dependencies !== null && current_dependencies_index < dependencies.length) {
remove_reactions(signal, current_dependencies_index);
dependencies.length = current_dependencies_index;
}
return res;
reaction.deps = current_dependencies;
return result;
} finally {
current_dependencies = previous_dependencies;
current_dependencies_index = previous_dependencies_index;
current_untracked_writes = previous_untracked_writes;
current_reaction = previous_reaction;
current_skip_reaction = previous_skip_reaction;
@ -810,26 +783,10 @@ export function get(signal) {
// Register the dependency on the current reaction signal.
if (current_reaction !== null) {
const unowned = (current_reaction.f & UNOWNED) !== 0;
const dependencies = current_reaction.deps;
if (
current_dependencies === null &&
dependencies !== null &&
dependencies[current_dependencies_index] === signal &&
!(unowned && current_effect !== null)
) {
current_dependencies_index++;
} else if (
dependencies === null ||
current_dependencies_index === 0 ||
dependencies[current_dependencies_index - 1] !== signal
) {
if (current_dependencies === null) {
current_dependencies = [signal];
} else if (current_dependencies[current_dependencies.length - 1] !== signal) {
current_dependencies.push(signal);
}
if (!current_dependencies?.includes(signal)) {
(current_dependencies ??= []).push(signal);
}
if (
current_untracked_writes !== null &&
current_effect !== null &&

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