verify impl and verify the xdb files

binding/javascript/ReadMe.md

@@ -22,7 +22,7 @@ let version = IPv6;
 ### 文件验证
 建议您主动去验证 xdb 文件的适用性，因为后期的一些新功能可能会导致目前的 Searcher 版本无法适用你使用的 xdb 文件，验证可以避免运行过程中的一些不可预测的错误。 你不需要每次都去验证，例如在服务启动的时候，或者手动调用命令验证确认版本匹配即可，不要在每次创建的 Searcher 的时候运行验证，这样会影响查询的响应速度，尤其是高并发的使用场景。
 ```javascript
-import verifyFomFile from './index.js';
+import verifyFromFile from './index.js';
 
 try {
     verifyFromFile(dbPath);
@@ -30,6 +30,7 @@ try {
     // 适用性验证失败！！！
     // 当前查询客户端实现不适用于 dbPath 指定的 xdb 文件的查询.
     // 应该停止启动服务，使用合适的 xdb 文件或者升级到适合 dbPath 的 Searcher 实现。
+    console.log(`binding is not applicable for xdb file '${dbPath}': ${e.message}`);
     return;
 }
 

binding/javascript/index.js

@@ -30,7 +30,9 @@ export {
     loadVectorIndex,
     loadVectorIndexFromFile,
     loadContent,
-    loadContentFromFile
+    loadContentFromFile,
+    verify,
+    verifyFromFile
 } from './util.js';
 
 export { 

binding/javascript/tests/search.test.js

@@ -5,7 +5,7 @@
 // searcher search tester
 // @Author Lion <chenxin619315@gmail.com>
 
-import {IPv4, IPv6, parseIP, ipToString, newWithFileOnly} from '../index.js';
+import {IPv4, IPv6, parseIP, ipToString, newWithFileOnly, verifyFromFile} from '../index.js';
 import path from 'path';
 import { fileURLToPath } from 'url';
 
@@ -16,6 +16,18 @@ const dbPath = {
 }
 
 test('ipv4 search test', async () => {
+    // verify the xdb file
+    // @Note: do NOT call it every time you create a searcher since this will slow
+    // down the search response.
+    // @see the verify function for details.
+    try {
+        verifyFromFile(dbPath.v4);
+        console.log(`xdb file '${dbPath.v4}' verified`);
+    } catch (e) {
+        console.log(`binding is not applicable for xdb file '${dbPath.v4}': ${e.message}`);
+        return;
+    }
+
     let searcher = newWithFileOnly(IPv4, dbPath.v4);
     let ip_list  = [
         '1.0.0.0',
@@ -38,6 +50,18 @@ test('ipv4 search test', async () => {
 });
 
 test('ipv6 search test', async () => {
+    // verify the xdb file
+    // @Note: do NOT call it every time you create a searcher since this will slow
+    // down the search response.
+    // @see the verify function for details.
+    try {
+        verifyFromFile(dbPath.v6);
+        console.log(`xdb file '${dbPath.v6}' verified`);
+    } catch (e) {
+        console.log(`binding is not applicable for xdb file '${dbPath.v6}': ${e.message}`);
+        return;
+    }
+
     let searcher = newWithFileOnly(IPv6, dbPath.v6);
     let ip_list  = [
         '2a02:26f7:c409:4001::',

binding/javascript/util.js

@@ -373,9 +373,42 @@ export function loadContent(fd) {
 export function loadContentFromFile(dbPath) {
     const fd = fs.openSync(dbPath, "r");
     const content = loadContent(fd);
-    fs.close(fd, function(){});
+    fs.closeSync(fd);
     return content;
 }
 
-const ipBytes = parseIP("2a02:26f7:c409:4001::");
-console.log(ipToString(ipBytes));
+// --- 
+
+// Verify if the current Searcher could be used to search the specified xdb file.
+// Why do we need this check ?
+// The future features of the xdb impl may cause the current searcher not able to work properly.
+//
+// @Note: You Just need to check this ONCE when the service starts
+// Or use another process (eg, A command) to check once Just to confirm the suitability.
+export function verify(fd) {
+    const header = loadHeader(fd);
+
+    // get the runtime ptr bytes
+    let runtimePtrBytes = 0;
+    if (header.version == XdbStructure20) {
+        runtimePtrBytes = 4;
+    } else if (header.version == XdbStructure30) {
+        runtimePtrBytes = header.runtimePtrBytes;
+    } else {
+        throw new Error(`invalid structure version ${header.version}`);
+    }
+
+    // 1, confirm the xdb file size
+    // to ensure that the maximum file pointer does not overflow
+    const maxFilePtr = (1n << BigInt(runtimePtrBytes * 8)) - 1n;
+    const _fileBytes = BigInt(fs.fstatSync(fd).size);
+    if (_fileBytes > maxFilePtr) {
+        throw new Error(`xdb file exceeds the maximum supported bytes: ${maxFilePtr}`);
+    }
+}
+
+export function verifyFromFile(dbPath) {
+    const fd = fs.openSync(dbPath, "r");
+    verify(fd);
+    fs.closeSync(fd);
+}