1 files changed, 183 insertions, 0 deletions
diff --git a/ext/js/settings/storage-controller.js b/ext/js/settings/storage-controller.js
new file mode 100644
index 00000000..c27c8690
--- /dev/null
+++ b/ext/js/settings/storage-controller.js
@@ -0,0 +1,183 @@
+/*
+ * Copyright (C) 2019-2021  Yomichan Authors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+class StorageController {
+    constructor() {
+        this._mostRecentStorageEstimate = null;
+        this._storageEstimateFailed = false;
+        this._isUpdating = false;
+        this._persistentStorageCheckbox = false;
+        this._storageUsageNode = null;
+        this._storageQuotaNode = null;
+        this._storageUseFiniteNodes = null;
+        this._storageUseInfiniteNodes = null;
+        this._storageUseValidNodes = null;
+        this._storageUseInvalidNodes = null;
+    }
+
+    prepare() {
+        this._persistentStorageCheckbox = document.querySelector('#storage-persistent-checkbox');
+        this._storageUsageNodes = document.querySelectorAll('.storage-usage');
+        this._storageQuotaNodes = document.querySelectorAll('.storage-quota');
+        this._storageUseFiniteNodes = document.querySelectorAll('.storage-use-finite');
+        this._storageUseInfiniteNodes = document.querySelectorAll('.storage-use-infinite');
+        this._storageUseValidNodes = document.querySelectorAll('.storage-use-valid');
+        this._storageUseInvalidNodes = document.querySelectorAll('.storage-use-invalid');
+
+        this._preparePersistentStorage();
+        this.updateStats();
+        this._persistentStorageCheckbox.addEventListener('change', this._onPersistentStorageCheckboxChange.bind(this), false);
+        document.querySelector('#storage-refresh').addEventListener('click', this.updateStats.bind(this), false);
+    }
+
+    async updateStats() {
+        if (this._isUpdating) { return; }
+
+        try {
+            this._isUpdating = true;
+
+            const estimate = await this._storageEstimate();
+            const valid = (estimate !== null);
+
+            // Firefox reports usage as 0 when persistent storage is enabled.
+            const finite = valid && (estimate.usage > 0 || !(await this._isStoragePeristent()));
+            if (finite) {
+                for (const node of this._storageUsageNodes) {
+                    node.textContent = this._bytesToLabeledString(estimate.usage);
+                }
+                for (const node of this._storageQuotaNodes) {
+                    node.textContent = this._bytesToLabeledString(estimate.quota);
+                }
+            }
+
+            this._setElementsVisible(this._storageUseFiniteNodes, valid && finite);
+            this._setElementsVisible(this._storageUseInfiniteNodes, valid && !finite);
+            this._setElementsVisible(this._storageUseValidNodes, valid);
+            this._setElementsVisible(this._storageUseInvalidNodes, !valid);
+
+            return valid;
+        } finally {
+            this._isUpdating = false;
+        }
+    }
+
+    // Private
+
+    async _preparePersistentStorage() {
+        if (!(navigator.storage && navigator.storage.persist)) {
+            // Not supported
+            return;
+        }
+
+        const info = document.querySelector('#storage-persistent-info');
+        if (info !== null) { info.hidden = false; }
+
+        const isStoragePeristent = await this._isStoragePeristent();
+        this._updateCheckbox(isStoragePeristent);
+
+        const button = document.querySelector('#storage-persistent-button');
+        if (button !== null) {
+            button.hidden = false;
+            button.addEventListener('click', this._onPersistStorageButtonClick.bind(this), false);
+        }
+    }
+
+    _onPersistentStorageCheckboxChange(e) {
+        const node = e.currentTarget;
+        if (!node.checked) {
+            node.checked = true;
+            return;
+        }
+        this._attemptPersistStorage();
+    }
+
+    _onPersistStorageButtonClick() {
+        const {checked} = this._persistentStorageCheckbox;
+        if (checked) { return; }
+        this._persistentStorageCheckbox.checked = !checked;
+        this._persistentStorageCheckbox.dispatchEvent(new Event('change'));
+    }
+
+    async _attemptPersistStorage() {
+        if (await this._isStoragePeristent()) { return; }
+
+        let isStoragePeristent = false;
+        try {
+            isStoragePeristent = await navigator.storage.persist();
+        } catch (e) {
+            // NOP
+        }
+
+        this._updateCheckbox(isStoragePeristent);
+
+        if (isStoragePeristent) {
+            this.updateStats();
+        } else {
+            const node = document.querySelector('#storage-persistent-fail-warning');
+            if (node !== null) { node.hidden = false; }
+        }
+    }
+
+    async _storageEstimate() {
+        if (this._storageEstimateFailed && this._mostRecentStorageEstimate === null) {
+            return null;
+        }
+        try {
+            const value = await navigator.storage.estimate();
+            this._mostRecentStorageEstimate = value;
+            return value;
+        } catch (e) {
+            this._storageEstimateFailed = true;
+        }
+        return null;
+    }
+
+    _bytesToLabeledString(size) {
+        const base = 1000;
+        const labels = [' bytes', 'KB', 'MB', 'GB', 'TB'];
+        const maxLabelIndex = labels.length - 1;
+        let labelIndex = 0;
+        while (size >= base && labelIndex < maxLabelIndex) {
+            size /= base;
+            ++labelIndex;
+        }
+        const label = labelIndex === 0 ? `${size}` : size.toFixed(1);
+        return `${label}${labels[labelIndex]}`;
+    }
+
+    async _isStoragePeristent() {
+        try {
+            return await navigator.storage.persisted();
+        } catch (e) {
+            // NOP
+        }
+        return false;
+    }
+
+    _updateCheckbox(isStoragePeristent) {
+        const checkbox = this._persistentStorageCheckbox;
+        checkbox.checked = isStoragePeristent;
+        checkbox.readOnly = isStoragePeristent;
+    }
+
+    _setElementsVisible(elements, visible) {
+        visible = !visible;
+        for (const element of elements) {
+            element.hidden = visible;
+        }
+    }
+}