Новый движок БД

server/db/JembaDb/utils.js

@@ -0,0 +1,152 @@
+const fsCB = require('fs');
+const fs = fsCB.promises;
+const zlib = require('zlib');
+
+function sleep(ms) {
+    return new Promise(resolve => setTimeout(resolve, ms));
+}
+
+function sleepWithStop(ms, cb = () => {}) {
+    return new Promise(resolve => {
+        const timer = setTimeout(resolve, ms);
+        cb(() => { clearTimeout(timer); resolve(); });
+    });
+}
+
+function unionSet(arrSet) {
+    if (!arrSet.length)
+        return new Set();
+
+    let max = 0;
+    let size = arrSet[0].size;
+    for (let i = 1; i < arrSet.length; i++) {
+        if (arrSet[i].size > size) {
+            max = i;
+            size = arrSet[i].size;
+        }
+    }
+
+    const result = new Set(arrSet[max]);
+    for (let i = 0; i < arrSet.length; i++) {
+        if (i === max)
+            continue;
+
+        for (const elem of arrSet[i]) {
+            result.add(elem);
+        }
+    }
+
+    return result;
+}
+
+function intersectSet(arrSet) {
+    if (!arrSet.length)
+        return new Set();
+
+    let min = 0;
+    let size = arrSet[0].size;
+    for (let i = 1; i < arrSet.length; i++) {
+        if (arrSet[i].size < size) {
+            min = i;
+            size = arrSet[i].size;
+        }
+    }
+
+    const result = new Set();
+    for (const elem of arrSet[min]) {
+        let inAll = true;
+        for (let i = 0; i < arrSet.length; i++) {
+            if (i === min)
+                continue;
+            if (!arrSet[i].has(elem)) {
+                inAll = false;
+                break;
+            }
+        }
+
+        if (inAll)
+            result.add(elem);
+    }
+
+
+    return result;
+}
+
+async function pathExists(path) {
+    try {
+        await fs.access(path);
+        return true;
+    } catch(e) {
+        return false;
+    }
+}
+
+async function appendFileToFile(nameFrom, nameTo) {
+    return new Promise((resolve, reject) => {
+        const readStream = fsCB.createReadStream(nameFrom);
+        readStream.on('error', (err) => {
+            reject(err);
+        });
+
+        const writeStream = fsCB.createWriteStream(nameTo, {flags: 'a'});
+
+        writeStream.on('error', (err) => {
+            reject(err);
+        });
+
+        writeStream.on('close', () => {
+            resolve();
+        });
+
+        readStream.pipe(writeStream);
+    });
+}
+
+function esc(obj) {
+    return JSON.stringify(obj).replace(/@/g, '\\x40');
+}
+
+function paramToArray(param) {
+    return (Array.isArray(param) ? param : [param]);
+}
+
+function cloneDeep(obj) {
+    return JSON.parse(JSON.stringify(obj));
+}
+
+//async
+function deflate(buf, compressionLevel) {
+    return new Promise((resolve, reject) => {
+        zlib.deflateRaw(buf, {level: compressionLevel}, (err, b) => {
+            if (err)
+                reject(err);
+            resolve(b);
+        });
+    });
+}
+
+//async
+function inflate(buf) {
+    return new Promise((resolve, reject) => {
+        zlib.inflateRaw(buf, (err, b) => {
+            if (err)
+                reject(err);
+            resolve(b);
+        });
+    });
+}
+
+
+module.exports = {
+    sleep,
+    sleepWithStop,
+    unionSet,
+    intersectSet,
+    pathExists,
+    appendFileToFile,
+    esc,
+    paramToArray,
+    cloneDeep,
+    deflate,
+    inflate,
+};