From c1b2954abd2d230c8feb1503d618af690255f29c Mon Sep 17 00:00:00 2001
From: cenfun <cenfun@gmail.com>
Date: Fri, 28 Jun 2024 22:20:46 +0800
Subject: [PATCH] improved performance for addFromDir

---
 CHANGELOG.md    |  3 ++
 lib/generate.js | 73 +++++++++++++++++++++++++++++++------------------
 lib/index.js    |  8 +-----
 3 files changed, 50 insertions(+), 34 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 118e050b..ac30fca2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,8 @@
 ## Changelog
 
+- 2.8.6
+  - improved performance
+
 - 2.8.5
   - fixed a sourcemap content issue
 
diff --git a/lib/generate.js b/lib/generate.js
index da758f85..51b76fbc 100644
--- a/lib/generate.js
+++ b/lib/generate.js
@@ -835,14 +835,11 @@ const resolveEntrySourceMap = (entry, sourceMapCache) => {
     }
 };
 
-const readCoverageData = (filePath, entryFilter, sourceCache) => {
+const readCoverageData = (item, entryFilter, sourceCache) => {
 
-    const content = fs.readFileSync(filePath).toString('utf-8');
-    if (!content) {
-        return;
-    }
+    const json = item.json;
 
-    const json = JSON.parse(content);
+    // raw v8 json
     let coverageData = json.result;
     if (!Util.isList(coverageData)) {
         return;
@@ -870,7 +867,7 @@ const readCoverageData = (filePath, entryFilter, sourceCache) => {
     return coverageData;
 };
 
-const readFromDir = async (dir, entryFilter, addHandler) => {
+const readFromDir = async (mcr, dir) => {
 
     if (!dir || !fs.existsSync(dir)) {
         Util.logInfo(`Not found V8 coverage dir: ${dir}`);
@@ -878,41 +875,63 @@ const readFromDir = async (dir, entryFilter, addHandler) => {
     }
 
     const files = fs.readdirSync(dir);
-    if (!files.length) {
+    const list = [];
+    files.forEach((filename) => {
+        if (filename.startsWith('coverage-')) {
+            list.push({
+                type: 'coverage',
+                filename
+            });
+            return;
+        }
+        if (filename.startsWith('source-')) {
+            list.push({
+                type: 'source',
+                filename
+            });
+        }
+    });
+
+    if (!list.length) {
         Util.logInfo(`No coverage files in the dir: ${dir}`);
         return;
     }
 
-    const coverageFiles = [];
+    const contentList = await Promise.all(list.map((it) => Util.readFile(path.resolve(dir, it.filename))));
     const sourceCache = {};
-    files.forEach((filename) => {
-        const isCoverage = filename.startsWith('coverage-');
-        if (isCoverage) {
-            coverageFiles.push(filename);
+    const coverageFiles = [];
+
+    contentList.forEach((content, i) => {
+        if (!content) {
             return;
         }
-        const isSource = filename.startsWith('source-');
-        if (isSource) {
-            const filePath = path.resolve(dir, filename);
-            const content = fs.readFileSync(filePath).toString('utf-8');
-            if (content) {
-                const json = JSON.parse(content);
-                if (json.url) {
-                    sourceCache[json.url] = json;
-                }
+        const json = JSON.parse(content);
+        if (!json) {
+            return;
+        }
+        const item = list[i];
+        if (item.type === 'source') {
+            if (json.url) {
+                sourceCache[json.url] = json;
             }
+        } else {
+            item.json = json;
+            coverageFiles.push(item);
         }
     });
 
-    // filter before adding
-    for (const filename of coverageFiles) {
-        const filePath = path.resolve(dir, filename);
-        const coverageData = readCoverageData(filePath, entryFilter, sourceCache);
+    const entryFilter = mcr.getEntryFilter();
+
+    const results = [];
+    for (const item of coverageFiles) {
+        const coverageData = readCoverageData(item, entryFilter, sourceCache);
         if (coverageData) {
-            await addHandler(coverageData);
+            const res = await mcr.add(coverageData);
+            results.push(res);
         }
     }
 
+    return results;
 };
 
 module.exports = {
diff --git a/lib/index.js b/lib/index.js
index fc0cfb8d..cb1f241a 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -124,14 +124,8 @@ class CoverageReport {
     // add coverage from dir
     async addFromDir(dir) {
         const time_start = Date.now();
-
-        const entryFilter = this.getEntryFilter();
-        const results = await readFromDir(dir, entryFilter, (coverageData) => {
-            return this.add(coverageData);
-        });
-
+        const results = await readFromDir(this, dir);
         Util.logTime(`added from dir: ${dir}`, time_start);
-
         return results;
     }