feat: getFileDistance() #3638

Author: Will-ShaoHua

src/shared/filesystemUtilities.ts

@@ -156,6 +156,35 @@ export function isInDirectory(d: string, p: string): boolean {
     })
 }
 
+/**
+ *
+ * @returns file distance between fileA and fileB
+ * For example:
+ * The file distance between A/B/C.java and A/B/D.java is 0
+ * The file distance between A/B/C.java and A/D.java is 1
+ */
+export function getFileDistance(fileA: string, fileB: string): number {
+    let filePathA = pathutils.normalize(fileA).split('/')
+    filePathA = filePathA.slice(0, filePathA.length - 1)
+
+    let filePathB = pathutils.normalize(fileB).split('/')
+    filePathB = filePathB.slice(0, filePathB.length - 1)
+
+    let i = 0
+    while (i < Math.min(filePathA.length, filePathB.length)) {
+        const dir1 = filePathA[i]
+        const dir2 = filePathB[i]
+
+        if (dir1 !== dir2) {
+            break
+        }
+
+        i++
+    }
+
+    return filePathA.slice(i).length + filePathB.slice(i).length
+}
+
 /**
  * Returns `name.suffix` if it does not already exist in directory `dir`, else appends
  * a number ("foo-1.txt", "foo-2.txt", etc.).

src/test/shared/filesystemUtilities.test.ts

@@ -9,6 +9,7 @@ import { writeFile, remove } from 'fs-extra'
 import * as path from 'path'
 import {
     fileExists,
+    getFileDistance,
     getNonexistentFilename,
     isInDirectory,
     makeTemporaryToolkitFolder,
@@ -119,4 +120,79 @@ describe('filesystemUtilities', function () {
             assert.ok(!isInDirectory('/foo/bar/baz/', '/FOO/BAR/BAZ/A.TXT'))
         }
     })
+
+    describe('getFileDistance', function () {
+        let fileA: string
+        let fileB: string
+
+        it('distance 0', function () {
+            fileA = 'foo/bar/a.java'
+            fileB = 'foo/bar/b.java'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 0)
+        })
+
+        it('root distance 0', function () {
+            fileA = 'a.txt'
+            fileB = 'b.txt'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 0)
+        })
+
+        it('distance 1', function () {
+            fileA = 'foo/bar/a.java'
+            fileB = 'foo/b.java'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 1)
+        })
+
+        it('distance 3', function () {
+            fileA = 'foo/bar/a.java'
+            fileB = 'lzz/b.java'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 3)
+        })
+
+        it('distance 4', function () {
+            fileA = 'foo/bar/a.java'
+            fileB = 'lzz/baz/b.java'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 4)
+        })
+
+        it('another distance 4', function () {
+            fileA = 'foo/a.py'
+            fileB = 'foo/foo/foo/foo/foo/b.py'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 4)
+        })
+
+        it('distance 5', function () {
+            fileA = 'foo/bar/a.java'
+            fileB = 'lzz/baz/zoo/b.java'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 5)
+        })
+
+        it('distance 6', function () {
+            fileA = 'foo/zoo/a.java'
+            fileB = 'bar/baz/bee/bww/b.java'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 6)
+        })
+
+        it('backslash distance 1', function () {
+            fileA = 'C:\\FOO\\BAR\\BAZ\\A.TXT'
+            fileB = 'C:\\FOO\\BAR\\B.TXT'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 1)
+        })
+
+        it('backslash distnace 3', function () {
+            fileA = 'C:\\FOO\\BAR\\BAZ\\LOO\\WOW\\A.txt'
+            fileB = 'C:\\FOO\\BAR\\B.txt'
+            const actual = getFileDistance(fileA, fileB)
+            assert.strictEqual(actual, 3)
+        })
+    })
 })