fix: fix awful inode autoincrement bug

Author: billiegoose

src/CacheFS.js

@@ -8,7 +8,7 @@ module.exports = class CacheFS {
     this._root = new Map([["/", this._makeRoot()]]);
   }
   _makeRoot(root = new Map()) {
-    root.set(STAT, { mode: 0o777, type: "dir", size: 0, mtimeMs: Date.now() });
+    root.set(STAT, { mode: 0o777, type: "dir", size: 0, ino: 0, mtimeMs: Date.now() });
     return root
   }
   loadSuperBlock(superblock) {
@@ -35,10 +35,10 @@ module.exports = class CacheFS {
     return val;
   }
   _maxInode(map) {
-    let max = 0;
+    let max = map.get(STAT).ino;
     for (let [key, val] of map) {
       if (key === STAT) continue;
-      max = Math.max(max, val.get(STAT).ino);
+      max = Math.max(max, this._maxInode(val));
     }
     return max;
   }
@@ -137,23 +137,28 @@ module.exports = class CacheFS {
     return [...dir.keys()].filter(key => typeof key === "string");
   }
   writeFile(filepath, data, { mode }) {
-    let oldStat;
+    let ino;
     try {
-      oldStat = this.stat(filepath);
+      let oldStat = this.stat(filepath);
+      if (mode === null) {
+        mode = oldStat.mode;
+      }
+      ino = oldStat.ino;
     } catch (err) {}
-    if (oldStat && mode == null) {
-      mode = oldStat.mode;
-    } else if (mode == null) {
+    if (mode == null) {
       mode = 0o666;
     }
+    if (ino == null) {
+      ino = this.autoinc();
+    }
     let dir = this._lookup(path.dirname(filepath));
     let basename = path.basename(filepath);
     let stat = {
       mode,
       type: "file",
       size: data.length,
       mtimeMs: Date.now(),
-      ino: this.autoinc(),
+      ino,
     };
     let entry = new Map();
     entry.set(STAT, stat);

src/__tests__/CacheFS.spec.js

@@ -1,19 +1,39 @@
 import CacheFS from "../CacheFS";
 
-const fs = new CacheFS();
-
 const treeText = require('./__fixtures__/tree.txt.js');
 
 describe("CacheFS module", () => {
   it("print ∘ parse == id", () => {
+    const fs = new CacheFS();
     let parsed = fs.parse(treeText)
     let text = fs.print(parsed)
     expect(text).toEqual(treeText)
   });
   it("size()", () => {
+    const fs = new CacheFS();
     expect(fs.size()).toEqual(0)
     fs.loadSuperBlock(treeText)
     let inodeCount = treeText.trim().split('\n').length
     expect(fs.size()).toEqual(inodeCount)
   });
+  it("autoinc()", () => {
+    const fs = new CacheFS();
+    expect(fs.autoinc()).toEqual(1)
+    fs.writeFile('/foo', 'bar', {})
+    expect(fs.autoinc()).toEqual(2)
+    fs.mkdir('/bar', {})
+    expect(fs.autoinc()).toEqual(3)
+    fs.unlink('/foo')
+    expect(fs.autoinc()).toEqual(3)
+    fs.mkdir('/bar/baz', {})
+    expect(fs.autoinc()).toEqual(4)
+    fs.rmdir('/bar/baz')
+    expect(fs.autoinc()).toEqual(3)
+    fs.mkdir('/bar/bar', {})
+    expect(fs.autoinc()).toEqual(4)
+    fs.writeFile('/bar/bar/boo', 'bar', {})
+    expect(fs.autoinc()).toEqual(5)
+    fs.unlink('/bar/bar/boo')
+    expect(fs.autoinc()).toEqual(4)
+  });
 });

src/__tests__/fs.spec.js

@@ -52,6 +52,25 @@ describe("fs module", () => {
         });
       });
     });
+    it("write file perserves old inode", done => {
+      fs.mkdir("/writeFile", err => {
+        fs.writeFile("/writeFile/writeFile-inode.txt", "HELLO", err => {
+          expect(err).toBe(null);
+          fs.stat("/writeFile/writeFile-inode.txt", (err, stats) => {
+            expect(err).toBe(null);
+            let inode = stats.ino;
+            fs.writeFile("/writeFile/writeFile-inode.txt", "WORLD", err => {
+              expect(err).toBe(null);
+              fs.stat("/writeFile/writeFile-inode.txt", (err, stats) => {
+                expect(err).toBe(null);
+                expect(stats.ino).toEqual(inode);
+                done();
+              });
+            });
+          });
+        });
+      });
+    });
   });
 
   describe("readFile", () => {