| 1 |
<?php |
| 2 |
/** |
| 3 |
* Optimizer — the autopilot loop. |
| 4 |
* |
| 5 |
* @package XSpeed |
| 6 |
*/ |
| 7 |
|
| 8 |
namespace XSpeed; |
| 9 |
|
| 10 |
defined( 'ABSPATH' ) || exit; |
| 11 |
|
| 12 |
/** |
| 13 |
* Apply an optimization plan one step at a time, verifying after each. |
| 14 |
* |
| 15 |
* The loop is deliberately boring, because the interesting part is what it |
| 16 |
* refuses to do: |
| 17 |
* |
| 18 |
* - **One change at a time.** A batch that fails tells you nothing about |
| 19 |
* which setting did it, and leaves you reverting work that was fine. |
| 20 |
* - **Purge before verifying.** No settings change purges the page cache on |
| 21 |
* its own (#205), so a check run against an unpurged site verifies the page |
| 22 |
* as it was BEFORE the change and passes anything. |
| 23 |
* - **Revert only the failing step.** A break at step 9 must not discard the |
| 24 |
* eight verified wins before it, and must not abort the four steps after. |
| 25 |
* - **Never leave a step applied-but-unverified.** If sampling itself fails, |
| 26 |
* that is not permission to assume success. |
| 27 |
* |
| 28 |
* Every side effect is injected rather than called directly, so the whole loop |
| 29 |
* is unit-testable without a WordPress install or a live site: the tests drive |
| 30 |
* it with an applier that records, and a sampler that breaks on cue. |
| 31 |
* |
| 32 |
* @since 1.2.0 |
| 33 |
*/ |
| 34 |
final class Optimizer { |
| 35 |
|
| 36 |
/** |
| 37 |
* Run a plan. |
| 38 |
* |
| 39 |
* @param array<int,array<string,mixed>> $steps Ordered steps from Optimize_Plan::build(). |
| 40 |
* @param array<string,mixed> $baseline Sample taken before anything changed. |
| 41 |
* @param array{ |
| 42 |
* apply:callable, |
| 43 |
* revert:callable, |
| 44 |
* purge:callable, |
| 45 |
* sample:callable, |
| 46 |
* now?:callable |
| 47 |
* } $io Injected side effects. |
| 48 |
* @param int $budget_seconds Wall-clock cap; 0 = uncapped. |
| 49 |
* @return array{applied:array<int,array<string,mixed>>,reverted:array<int,array<string,mixed>>,skipped:array<int,array<string,string>>} |
| 50 |
*/ |
| 51 |
public static function run( array $steps, array $baseline, array $io, int $budget_seconds = 0 ): array { |
| 52 |
$apply = $io['apply']; |
| 53 |
$revert = $io['revert']; |
| 54 |
$purge = $io['purge']; |
| 55 |
$sample = $io['sample']; |
| 56 |
$now = $io['now'] ?? static function () { |
| 57 |
return time(); |
| 58 |
}; |
| 59 |
|
| 60 |
$started = (int) $now(); |
| 61 |
$applied = array(); |
| 62 |
$reverted = array(); |
| 63 |
$skipped = array(); |
| 64 |
|
| 65 |
foreach ( $steps as $i => $step ) { |
| 66 |
// Budget check BEFORE applying, never mid-step: stopping between |
| 67 |
// "wrote the setting" and "verified it" is the one state this |
| 68 |
// loop must never end in. |
| 69 |
if ( $budget_seconds > 0 && ( (int) $now() - $started ) >= $budget_seconds ) { |
| 70 |
foreach ( array_slice( $steps, $i ) as $rest ) { |
| 71 |
$skipped[] = array( |
| 72 |
'id' => (string) $rest['id'], |
| 73 |
'why' => __( 'Ran out of time before this step.', 'xspeed' ), |
| 74 |
); |
| 75 |
} |
| 76 |
break; |
| 77 |
} |
| 78 |
|
| 79 |
$before = self::snapshot_of( $step ); |
| 80 |
|
| 81 |
$apply( $step ); |
| 82 |
$purge(); |
| 83 |
|
| 84 |
$current = $sample(); |
| 85 |
|
| 86 |
// A sample we could not take is NOT a pass. Treating an |
| 87 |
// unreachable site as "probably fine" is how an autopilot leaves |
| 88 |
// a site broken and reports success. |
| 89 |
if ( ! is_array( $current ) ) { |
| 90 |
$revert( $step, $before ); |
| 91 |
$purge(); |
| 92 |
$reverted[] = array( |
| 93 |
'id' => (string) $step['id'], |
| 94 |
'why' => __( 'Could not load the page to check it, so the change was undone.', 'xspeed' ), |
| 95 |
); |
| 96 |
continue; |
| 97 |
} |
| 98 |
|
| 99 |
$check = Optimize_Verifier::compare( $baseline, $current ); |
| 100 |
if ( ! $check['ok'] ) { |
| 101 |
$revert( $step, $before ); |
| 102 |
$purge(); |
| 103 |
$reverted[] = array( |
| 104 |
'id' => (string) $step['id'], |
| 105 |
'why' => implode( ' ', $check['failures'] ), |
| 106 |
); |
| 107 |
continue; |
| 108 |
} |
| 109 |
|
| 110 |
$applied[] = array( |
| 111 |
'id' => (string) $step['id'], |
| 112 |
'change' => (string) $step['label'], |
| 113 |
'verified' => true, |
| 114 |
); |
| 115 |
} |
| 116 |
|
| 117 |
return array( |
| 118 |
'applied' => $applied, |
| 119 |
'reverted' => $reverted, |
| 120 |
'skipped' => $skipped, |
| 121 |
); |
| 122 |
} |
| 123 |
|
| 124 |
/** |
| 125 |
* The values to put back if this step has to be undone. |
| 126 |
* |
| 127 |
* Every step in the catalog turns something ON, so the inverse is the |
| 128 |
* same keys set to false. Kept as its own method so a future step whose |
| 129 |
* inverse is not simply `false` has one obvious place to say so, rather |
| 130 |
* than the revert path quietly writing the wrong thing. |
| 131 |
* |
| 132 |
* @param array<string,mixed> $step Step definition. |
| 133 |
* @return array<string,mixed> |
| 134 |
*/ |
| 135 |
private static function snapshot_of( array $step ): array { |
| 136 |
$out = array(); |
| 137 |
foreach ( (array) $step['values'] as $key => $value ) { |
| 138 |
$out[ $key ] = is_bool( $value ) ? ! $value : false; |
| 139 |
} |
| 140 |
return $out; |
| 141 |
} |
| 142 |
} |
| 143 |
|
