fix: do not prefix /ipfs/ source paths in window.ipfs.files.cp

This fixes bug B from
#530

add-on/src/lib/ipfs-proxy/pre-mfs-scope.js

@@ -1,5 +1,6 @@
 // Use path-browserify for consistent behavior between browser and tests on Windows
 const Path = require('path-browserify')
+const IsIpfs = require('is-ipfs')
 const DEFAULT_ROOT_PATH = '/dapps'
 
 // Creates a "pre" function that is called prior to calling a real function
@@ -42,13 +43,26 @@ const MfsPre = {
 // Scope a src/dest tuple to the app path
 function createSrcDestPre (getScope, getIpfs, rootPath) {
   return async (...args) => {
+    // console.log('createSrcDestPre.args.before: ' + JSON.stringify(args))
     const appPath = await getAppPath(getScope, getIpfs, rootPath)
-    args[0][0] = Path.join(appPath, safePath(args[0][0]))
+    // console.log('createSrcDestPre.args.appPath', appPath)
+    args[0][0] = safeSourcePathPrefix(appPath, args[0][0])
     args[0][1] = Path.join(appPath, safePath(args[0][1]))
+    // console.log('createSrcDestPre.args.after: ' + JSON.stringify(args))
     return args
   }
 }
 
+// Add a prefix to a src path in a safe way
+function safeSourcePathPrefix (prefix, path) {
+  const realPath = safePath(path)
+  if (IsIpfs.ipfsPath(realPath)) {
+    // we don't prefix valid /ipfs/ paths (public and immutable, so safe as-is)
+    return realPath
+  }
+  return Path.join(prefix, realPath)
+}
+
 // Scope a src path to the app path
 function createSrcPre (getScope, getIpfs, rootPath) {
   return async (...args) => {

test/functional/lib/ipfs-proxy/pre-mfs-scope.test.js

@@ -22,6 +22,17 @@ describe('lib/ipfs-proxy/pre-mfs-scope', () => {
     expect(args[0][1]).to.equal('/test-dapps/https/ipfs.io/destination.txt')
   })
 
+  it('should not scope src path if it is valid /ipfs/ path for files.cp', async () => {
+    // Bug B from https://github.com/ipfs-shipyard/ipfs-companion/issues/530#issue-341352979
+    const fnName = 'files.cp'
+    const getScope = () => 'https://ipfs.io/'
+    const getIpfs = () => ({ files: { mkdir: () => Promise.resolve() } })
+    const pre = createPreMfsScope(fnName, getScope, getIpfs, '/test-dapps')
+    const args = await pre(['/ipfs/bafkreigh2akiscaildcqabsyg3dfr6chu3fgpregiymsck7e7aqa4s52zy', '/destination.jpg'])
+    expect(args[0][0]).to.equal('/ipfs/bafkreigh2akiscaildcqabsyg3dfr6chu3fgpregiymsck7e7aqa4s52zy')
+    expect(args[0][1]).to.equal('/test-dapps/https/ipfs.io/destination.jpg')
+  })
+
   it('should scope src path for files.mkdir', async () => {
     const fnName = 'files.mkdir'
     const getScope = () => 'https://ipfs.io/'