add check before writing file

Author: viankakrisna

index.js

@@ -6,11 +6,13 @@ var fs = require("fs")
 var findCacheDir = require("find-cache-dir")
 var objectHash = require("object-hash")
 var os = require("os")
+var path = require("path")
 
 var engines = {}
 var rules = {}
 var cache = null
 var cachePath = null
+var cacheFallback =  path.join(os.tmpdir(), "eslint-loader", "cache.json")
 
 /**
  * linter
@@ -59,13 +61,25 @@ function lint(input, config, webpack) {
     res = engine.executeOnText(input, resourcePath, true)
 
     // Save new results in the cache
-    if (config.cache) {
+    if (config.cache && cachePath) {
       cache[resourcePath] = {
         hash: inputMD5,
         rules: rulesHash,
         res: res,
       }
-      fs.writeFileSync(cachePath, JSON.stringify(cache))
+      var cacheJson = JSON.stringify(cache)
+      try {
+        safeWriteCache(cachePath, cacheJson)
+      } 
+      catch (e) {
+        try {
+          cachePath = cacheFallback
+          safeWriteCache(cachePath, cacheJson)
+        } 
+        catch (e) {
+          cache = false
+        }
+      }
     }
   }
 
@@ -176,13 +190,13 @@ module.exports = function(input, map) {
   // Read the cached information only once and if enable
   if (cache === null) {
     if (config.cache) {
-      var thunk = findCacheDir({
-        name: "eslint-loader",
-        thunk: true,
-        create: true,
-      })
-      cachePath = thunk("data.json") || os.tmpdir() + "/data.json"
       try {
+        var thunk = findCacheDir({
+          name: "eslint-loader",
+          thunk: true,
+          create: true,
+        })
+        cachePath = thunk("data.json")
         cache = require(cachePath)
       }
       catch (e) {
@@ -197,3 +211,13 @@ module.exports = function(input, map) {
   lint(input, config, this)
   this.callback(null, input, map)
 }
+
+function safeWriteCache(cachePath, cacheJson) {
+  if (fs.existsSync(cachePath)) {
+    fs.writeFileSync(cachePath, cacheJson)
+  } 
+  else {
+    fs.mkdirSync(path.dirname(cachePath))
+    fs.writeFileSync(cachePath, cacheJson)
+  }
+}