Change Directory.create to not fail on existing directory with that name.

The new semantics is to ensure that a directory with that name
exists. There is no way to reliably guard a create call against
existing directories in an async program.

R=sgjesse@google.com
BUG=

Review URL: https://codereview.chromium.org//11175054

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@13933 260f80e4-7a28-3924-810f-c04153c831b5

runtime/bin/directory.dart

@@ -38,15 +38,18 @@ abstract class Directory {
   bool existsSync();
 
   /**
-   * Creates the directory with this name if it does not
-   * exist. Returns a [:Future<Directory>:] that completes with this
-   * directory once it has been created.
+   * Creates the directory with this name. If the directory already
+   * exists nothing is done. Returns a [:Future<Directory>:] that
+   * completes with this directory once it has been created. If the
+   * directory does not exist and cannot be created the future
+   * completes with an exception.
    */
   Future<Directory> create();
 
   /**
-   * Synchronously creates the directory with this name if it does not exist.
-   * Throws an exception if the directory already exists.
+   * Synchronously creates the directory with this name. If the
+   * directory already exists nothing is done. If the directory does
+   * not exist and cannot be created an exception is thrown.
    */
   void createSync();
 

runtime/bin/directory_linux.cc

@@ -381,6 +381,9 @@ char* Directory::Current() {
 
 
 bool Directory::Create(const char* dir_name) {
+  // If the directory already exists and is a directory do not
+  // attempt to create it again and treat it as a success.
+  if (Exists(dir_name) == EXISTS) return true;
   // Create the directory with the permissions specified by the
   // process umask.
   return (TEMP_FAILURE_RETRY(mkdir(dir_name, 0777)) == 0);

runtime/bin/directory_macos.cc

@@ -381,6 +381,9 @@ char* Directory::Current() {
 
 
 bool Directory::Create(const char* dir_name) {
+  // If the directory already exists and is a directory do not
+  // attempt to create it again and treat it as a success.
+  if (Exists(dir_name) == EXISTS) return true;
   // Create the directory with the permissions specified by the
   // process umask.
   return (TEMP_FAILURE_RETRY(mkdir(dir_name, 0777)) == 0);

runtime/bin/directory_win.cc

@@ -348,6 +348,9 @@ char* Directory::Current() {
 
 
 bool Directory::Create(const char* dir_name) {
+  // If the directory already exists and is a directory do not
+  // attempt to create it again and treat it as a success.
+  if (Exists(dir_name) == EXISTS) return true;
   return (CreateDirectory(dir_name, NULL) != 0);
 }
 

tests/standalone/io/directory_test.dart

@@ -16,6 +16,7 @@ class DirectoryTest {
     Directory subDirectory = new Directory("${directory.path}/subdir");
     Expect.isFalse(subDirectory.existsSync());
     subDirectory.createSync();
+    Expect.isTrue(subDirectory.existsSync());
     File f = new File('${subDirectory.path}/file.txt');
     Expect.isFalse(f.existsSync());
     f.createSync();
@@ -459,6 +460,83 @@ testCreateTempError() {
 }
 
 
+testCreateExistingSync() {
+  // Test that creating an existing directory succeeds.
+  var d = new Directory('');
+  var temp = d.createTempSync();
+  var subDir = new Directory('${temp.path}/flaf');
+  Expect.isFalse(subDir.existsSync());
+  subDir.createSync();
+  Expect.isTrue(subDir.existsSync());
+  subDir.createSync();
+  Expect.isTrue(subDir.existsSync());
+  temp.deleteRecursivelySync();
+}
+
+
+testCreateExisting() {
+  // Test that creating an existing directory succeeds.
+  var port = new ReceivePort();
+  var d = new Directory('');
+  d.createTemp().then((temp) {
+    var subDir = new Directory('${temp.path}/flaf');
+    subDir.exists().then((dirExists) {
+      Expect.isFalse(dirExists);
+      subDir.create().then((_) {
+        subDir.exists().then((dirExists) {
+          Expect.isTrue(dirExists);
+          subDir.create().then((_) {
+            subDir.exists().then((dirExists) {
+              Expect.isTrue(dirExists);
+              temp.deleteRecursively().then((_) {
+                port.close();
+              });
+            });
+          });
+        });
+      });
+    });
+  });
+}
+
+
+testCreateDirExistingFileSync() {
+  // Test that creating an existing directory succeeds.
+  var d = new Directory('');
+  var temp = d.createTempSync();
+  var path = '${temp.path}/flaf';
+  var file = new File(path);
+  file.createSync();
+  Expect.isTrue(file.existsSync());
+  Expect.throws(new Directory(path).createSync,
+                (e) => e is DirectoryIOException);
+  temp.deleteRecursivelySync();
+}
+
+
+testCreateDirExistingFile() {
+  // Test that creating an existing directory succeeds.
+  var port = new ReceivePort();
+  var d = new Directory('');
+  d.createTemp().then((temp) {
+    var path = '${temp.path}/flaf';
+    var file = new File(path);
+    var subDir = new Directory(path);
+    file.create().then((_) {
+      subDir.create()
+        ..then((_) { Expect.fail("dir create should fail on existing file"); })
+        ..handleException((e) {
+            Expect.isTrue(e is DirectoryIOException);
+            temp.deleteRecursively().then((_) {
+              port.close();
+            });
+            return true;
+          });
+    });
+  });
+}
+
+
 testRename() {
   var d = new Directory('');
   var temp1 = d.createTempSync();
@@ -483,5 +561,9 @@ main() {
   NestedTempDirectoryTest.testMain();
   testCreateTempErrorSync();
   testCreateTempError();
+  testCreateExistingSync();
+  testCreateExisting();
+  testCreateDirExistingFileSync();
+  testCreateDirExistingFile();
   testRename();
 }