| @@ -40,9 +40,9 @@ | ||
| 40 | 40 | // can't leak it on a fatal PHP error. |
| 41 | 41 | $lock_acquired = $this->acquireNumberLock(); |
| 42 | 42 | try { |
| 43 | 43 | // Get the next number to use |
| 44 | - $next_number = get_option('easy_invoice_next_invoice_number', 1); | |
| 44 | + $next_number = $this->freshCounter(); | |
| 45 | 45 | |
| 46 | 46 | // Find the next unique number |
| 47 | 47 | $unique_number = $this->findNextUniqueNumber($next_number, $prefix); |
| 48 | 48 | |
| @@ -116,9 +116,9 @@ | ||
| 116 | 116 | // lock so neither call site is a race window. |
| 117 | 117 | $lock_acquired = $this->acquireNumberLock(); |
| 118 | 118 | try { |
| 119 | 119 | // Get the next number to use from the current settings |
| 120 | - $next_number = get_option('easy_invoice_next_invoice_number', 1); | |
| 120 | + $next_number = $this->freshCounter(); | |
| 121 | 121 | |
| 122 | 122 | // Find the next unique number |
| 123 | 123 | $unique_number = $this->findNextUniqueNumber($next_number, $prefix); |
| 124 | 124 | |
| @@ -146,8 +146,60 @@ | ||
| 146 | 146 | * Timeout is 3s — if the database is so contended that even this |
| 147 | 147 | * fails, blocking the user's create-invoice request longer is |
| 148 | 148 | * worse than the residual race risk. |
| 149 | 149 | */ |
| 150 | + /** | |
| 151 | + * Keep a number a form submitted, or hand out a fresh one. | |
| 152 | + * | |
| 153 | + * The builder pre-fills its number field with the next number without | |
| 154 | + * taking it, so two people who opened "New" at the same time both post | |
| 155 | + * the same number. Under the number lock: a number nobody uses yet is | |
| 156 | + * kept, and if it is the counter's next value the counter moves past | |
| 157 | + * it; a number already in use is replaced by a freshly generated one. | |
| 158 | + * | |
| 159 | + * @param string $requested The number the form sent, possibly empty. | |
| 160 | + * @return string The number to save. | |
| 161 | + */ | |
| 162 | + public function claimOrGenerate(string $requested): string { | |
| 163 | + $requested = trim($requested); | |
| 164 | + if ($requested === '') { | |
| 165 | + return $this->generateUniqueNumber(); | |
| 166 | + } | |
| 167 | + $lock_acquired = $this->acquireNumberLock(); | |
| 168 | + try { | |
| 169 | + if ($this->numberExists($requested)) { | |
| 170 | + return $this->generateUniqueNumber(); | |
| 171 | + } | |
| 172 | + $prefix = get_option('easy_invoice_invoice_prefix', 'INV-'); | |
| 173 | + $next = $this->freshCounter(); | |
| 174 | + if ($requested === $prefix . str_pad((string) $next, 6, '0', STR_PAD_LEFT)) { | |
| 175 | + update_option('easy_invoice_next_invoice_number', $next + 1); | |
| 176 | + } | |
| 177 | + return $requested; | |
| 178 | + } finally { | |
| 179 | + if ($lock_acquired) { | |
| 180 | + $this->releaseNumberLock(); | |
| 181 | + } | |
| 182 | + } | |
| 183 | + } | |
| 184 | + | |
| 185 | + /** | |
| 186 | + * The counter as the database holds it right now. | |
| 187 | + * | |
| 188 | + * Every request loads the options table into memory at boot, before | |
| 189 | + * it queues for the number lock, so a plain get_option() inside the | |
| 190 | + * lock returns whatever the counter was when *this* request started — | |
| 191 | + * and twelve simultaneous saves all "uniquely" took the same number. | |
| 192 | + * Drop the cached copy and read it again once the lock is held. | |
| 193 | + * | |
| 194 | + * @return int | |
| 195 | + */ | |
| 196 | + private function freshCounter(): int { | |
| 197 | + wp_cache_delete('easy_invoice_next_invoice_number', 'options'); | |
| 198 | + wp_cache_delete('alloptions', 'options'); | |
| 199 | + return (int) get_option('easy_invoice_next_invoice_number', 1); | |
| 200 | + } | |
| 201 | + | |
| 150 | 202 | private function acquireNumberLock(): bool { |
| 151 | 203 | global $wpdb; |
| 152 | 204 | $result = $wpdb->get_var($wpdb->prepare( |
| 153 | 205 | 'SELECT GET_LOCK(%s, %d)', |
