moving out note revision content into separate table, refactoring, WIP

src/entities/note_revision.js

@@ -3,6 +3,9 @@
 const Entity = require('./entity');
 const protectedSessionService = require('../services/protected_session');
 const repository = require('../services/repository');
+const utils = require('../services/utils');
+const dateUtils = require('../services/date_utils');
+const syncTableService = require('../services/sync_table');
 
 /**
  * NoteRevision represents snapshot of note's title and content at some point in the past. It's used for seamless note versioning.
@@ -12,7 +15,6 @@ const repository = require('../services/repository');
  * @param {string} type
  * @param {string} mime
  * @param {string} title
- * @param {string} content
  * @param {string} isProtected
  * @param {string} dateModifiedFrom
  * @param {string} dateModifiedTo
@@ -24,7 +26,7 @@ const repository = require('../services/repository');
 class NoteRevision extends Entity {
     static get entityName() { return "note_revisions"; }
     static get primaryKeyName() { return "noteRevisionId"; }
-    static get hashedProperties() { return ["noteRevisionId", "noteId", "title", "content", "isProtected", "dateModifiedFrom", "dateModifiedTo", "utcDateModifiedFrom", "utcDateModifiedTo"]; }
+    static get hashedProperties() { return ["noteRevisionId", "noteId", "title", "isProtected", "dateModifiedFrom", "dateModifiedTo", "utcDateModifiedFrom", "utcDateModifiedTo"]; }
 
     constructor(row) {
         super(row);
@@ -32,7 +34,12 @@ class NoteRevision extends Entity {
         this.isProtected = !!this.isProtected;
 
         if (this.isProtected) {
-            protectedSessionService.decryptNoteRevision(this);
+            if (protectedSessionService.isProtectedSessionAvailable()) {
+                this.title = protectedSessionService.decrypt(this.title);
+            }
+            else {
+                this.title = "[Protected]";
+            }
         }
     }
 
@@ -40,12 +47,97 @@ class NoteRevision extends Entity {
         return await repository.getEntity("SELECT * FROM notes WHERE noteId = ?", [this.noteId]);
     }
 
-    beforeSaving() {
-        if (this.isProtected) {
-            protectedSessionService.encryptNoteRevision(this);
+    /** @returns {boolean} true if the note has string content (not binary) */
+    isStringNote() {
+        return utils.isStringNote(this.type, this.mime);
+    }
+
+    /*
+     * Note revision content has quite special handling - it's not a separate entity, but a lazily loaded
+     * part of NoteRevision entity with it's own sync. Reason behind this hybrid design is that
+     * content can be quite large and it's not necessary to load it / fill memory for any note access even
+     * if we don't need a content, especially for bulk operations like search.
+     *
+     * This is the same approach as is used for Note's content.
+     */
+
+    /** @returns {Promise<*>} */
+    async getContent(silentNotFoundError = false) {
+        if (this.content === undefined) {
+            const res = await sql.getRow(`SELECT content, hash FROM note_revision_contents WHERE noteRevisionId = ?`, [this.noteRevisionId]);
+
+            if (!res) {
+                if (silentNotFoundError) {
+                    return undefined;
+                }
+                else {
+                    throw new Error("Cannot find note revision content for noteRevisionId=" + this.noteRevisionId);
+                }
+            }
+
+            this.content = res.content;
+
+            if (this.isProtected) {
+                if (protectedSessionService.isProtectedSessionAvailable()) {
+                    this.content = protectedSessionService.decrypt(this.content);
+                }
+                else {
+                    this.content = "";
+                }
+            }
+
+            if (this.isStringNote()) {
+                this.content = this.content === null
+                    ? ""
+                    : this.content.toString("UTF-8");
+            }
         }
 
-        super.beforeSaving();
+        return this.content;
+    }
+
+    /** @returns {Promise} */
+    async setContent(content) {
+        // force updating note itself so that dateChanged is represented correctly even for the content
+        this.forcedChange = true;
+        await this.save();
+
+        this.content = content;
+
+        const pojo = {
+            noteRevisionId: this.noteRevisionId,
+            content: content,
+            utcDateModified: dateUtils.utcNowDateTime(),
+            hash: utils.hash(this.noteRevisionId + "|" + content)
+        };
+
+        if (this.isProtected) {
+            if (protectedSessionService.isProtectedSessionAvailable()) {
+                pojo.content = protectedSessionService.encrypt(pojo.content);
+            }
+            else {
+                throw new Error(`Cannot update content of noteRevisionId=${this.noteRevisionId} since we're out of protected session.`);
+            }
+        }
+
+        await sql.upsert("note_revision_contents", "noteRevisionId", pojo);
+
+        await syncTableService.addNoteContentSync(this.noteId);
+    }
+
+    // cannot be static!
+    updatePojo(pojo) {
+        if (pojo.isProtected) {
+            if (protectedSessionService.isProtectedSessionAvailable()) {
+                pojo.title = protectedSessionService.encrypt(pojo.title);
+            }
+            else {
+                // updating protected note outside of protected session means we will keep original ciphertexts
+                delete pojo.title;
+            }
+        }
+
+        delete pojo.content;
     }
 }