update

lib/migrate.js

@@ -0,0 +1,98 @@
+'use strict';
+
+const { devWarn } = require('./log');
+
+// clips -> clips_fts 的同步触发器。v2 / v3 共用。
+const FTS_TRIGGERS = `
+  CREATE TRIGGER IF NOT EXISTS clips_ai AFTER INSERT ON clips BEGIN
+    INSERT INTO clips_fts(rowid, text) VALUES (new.id, new.text);
+  END;
+  CREATE TRIGGER IF NOT EXISTS clips_ad AFTER DELETE ON clips BEGIN
+    INSERT INTO clips_fts(clips_fts, rowid, text) VALUES('delete', old.id, old.text);
+  END;
+  -- 只在 text 真的变了才重建索引。没有这个 WHEN 的话，每次
+  -- "UPDATE clips SET top_at = ?"（也就是每次复制/置顶）都会白白
+  -- 把该行从 FTS 删掉再插回去。
+  CREATE TRIGGER IF NOT EXISTS clips_au AFTER UPDATE ON clips
+  WHEN old.text IS NOT new.text BEGIN
+    INSERT INTO clips_fts(clips_fts, rowid, text) VALUES('delete', old.id, old.text);
+    INSERT INTO clips_fts(rowid, text) VALUES (new.id, new.text);
+  END;
+`;
+
+// STEPS[i] upgrades the schema from version (i + 1) to (i + 2).
+// STEPS[0] therefore is the v1 -> v2 step.
+const STEPS = [
+  // v1 -> v2: add FTS5 table + triggers (idempotent).
+  function v1_to_v2(db) {
+    db.exec(`
+      CREATE VIRTUAL TABLE IF NOT EXISTS clips_fts USING fts5(text, content='clips', content_rowid='id');
+      ${FTS_TRIGGERS}
+      INSERT INTO clips_fts(rowid, text) SELECT id, text FROM clips WHERE text IS NOT NULL;
+    `);
+  },
+
+  // v2 -> v3: 换成 trigram 分词器。
+  //
+  // v2 用的是默认的 unicode61 分词器，它把一整串连续的中文当成**一个** token，
+  // 而 FTS5 的 MATCH 是整 token 匹配、不做子串匹配。结果：搜"公园"在
+  // "今天去公园散步"里一条都搜不到 —— 对一个中文剪贴板工具来说等于搜索全废。
+  // （v2 这一步之前因为索引下标算错从没真正执行过，所以线上一直悄悄退回 LIKE，
+  //   反而"正好"是对的；把 v2 修好之后这个坑才会暴露出来。）
+  //
+  // trigram 分词器按 3 字符滑窗切分，支持子串匹配，中文可用。
+  // 代价：≤2 字符的查询它匹配不到，这部分由调用方退回 LIKE 处理。
+  function v2_to_v3(db) {
+    db.exec(`
+      DROP TRIGGER IF EXISTS clips_ai;
+      DROP TRIGGER IF EXISTS clips_ad;
+      DROP TRIGGER IF EXISTS clips_au;
+      DROP TABLE IF EXISTS clips_fts;
+      CREATE VIRTUAL TABLE clips_fts USING fts5(
+        text, content='clips', content_rowid='id', tokenize='trigram'
+      );
+      ${FTS_TRIGGERS}
+      INSERT INTO clips_fts(rowid, text) SELECT id, text FROM clips WHERE text IS NOT NULL;
+    `);
+  },
+];
+
+/**
+ * Applies each pending schema step in order.
+ *
+ * The DB's own `PRAGMA user_version` is the source of truth for what has already
+ * been applied — not the config file, which only records the version the app
+ * *wants*. Passing a config-derived `fromVersion` would re-run every step on
+ * every launch (re-indexing the whole FTS table each time the app starts).
+ *
+ * Returns the version actually reached, so callers can tell whether a step was
+ * skipped because of an error.
+ */
+function migrate(db, fromVersion, toVersion) {
+  let current = fromVersion;
+  try {
+    const row = db.pragma('user_version', { simple: true });
+    if (typeof row === 'number' && row > 0) current = row;
+  } catch (e) {
+    // Non-sqlite stub (tests) — fall back to the caller-supplied version.
+  }
+
+  for (let v = current + 1; v <= toVersion; v++) {
+    const step = STEPS[v - 2];
+    if (!step) continue;
+    try {
+      step(db);
+      current = v;
+      try { db.pragma(`user_version = ${v}`); } catch (e) {}
+    } catch (e) {
+      // Most likely FTS5 is not compiled into this SQLite build. Leave the
+      // version marker where it is so a later launch can retry, and let the
+      // caller fall back to LIKE-based search.
+      devWarn('[migrate] step', v, 'failed, leaving schema at v' + current + ':', e.message);
+      break;
+    }
+  }
+  return current;
+}
+
+module.exports = { migrate, STEPS };