[jira] [Commented] (CB-453) FileWriter.append - Chinese characters are not appended to the file correctly

["Joe Bowser (Commented) (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CB-453?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13247857#comment-13247857 ] 

Joe Bowser commented on CB-453:
-------------------------------

The problem appears to be in FileWriter.truncateFile, which FileWriter.write depends on.  It writes in the wrong spot of the file, and Javascript isn't sending in the proper offsets for multibyte characters.
                
> FileWriter.append - Chinese characters are not appended to the file correctly
> -----------------------------------------------------------------------------
>
>                 Key: CB-453
>                 URL: https://issues.apache.org/jira/browse/CB-453
>             Project: Apache Callback
>          Issue Type: Bug
>          Components: Android
>    Affects Versions: 1.5.0
>         Environment:     test("should be able to write and append to file in Chinese Traditional, createWriter", function() {
>         QUnit.stop(Tests.TEST_TIMEOUT);
>         expect(2);
>         var that = this,
>             fileName = "writer.chinese",
>             filePath = this.root.fullPath + '/' + fileName,
>             // file content
>             rule = "每個規則有一個例外。",
>             // for testing file length
>             length = rule.length,
>             // writes initial file content
>             write_file = function(fileEntry) {
>                 fileEntry.createWriter(function(writer) {
>                     writer.onwriteend = function(evt) {
>                         // valid writing of non-ascii file was already validated in previous test.
>                         // Append to file to verify writer.length and writer.position are set correctly
>                         append_file(writer);
>                     };
>                     writer.write(rule); 
>                 }, that.fail);
>             }, 
>             // appends to file
>             append_file = function(writer) {
>                 var exception = "  除了這一個";            
>                 writer.onwriteend = function(evt) {
>                     // read back file to verify that data was appended
>                     var reader = new FileReader();
>                     reader.onloadend = function(evt) {
>                         console.log("old: " + rule + exception);
>                         console.log("new: " + evt.target.result);
>                         console.log("old: " + length);
>                         console.log("new: " + evt.target.result.length);
>                         
>                         ok(evt.target.result === (rule + exception), "reader.result after append should be equal to the text written.");
>                         ok(evt.target.result.length === length, "reader.result length should equal initial length.");
>                         // cleanup
>                         //that.deleteFile(fileName);
>                         QUnit.start();
>                     };
>                     var myFile = new File();
>                     myFile.fullPath = filePath; 
>                     reader.readAsText(myFile);
>                 };
>                 length += exception.length;
>                 console.log("len: " + writer.length);
>                 writer.seek(writer.length);
>                 console.log("pos: " + writer.position);
>                 writer.write(exception); 
>             };
>         
>         // create file, then write and append to it
>         this.createFile(fileName, write_file);
>     });
>            Reporter: Simon MacDonald
>            Assignee: Simon MacDonald
>             Fix For: 1.6.0
>
>
> When Becky checked in her update to the automated file tests (https://git-wip-us.apache.org/repos/asf?p=incubator-cordova-mobile-spec.git;a=commit;h=db377f9f2b4c5507b6eb1fcb8eb4fa029030cdef) the test to check if you could append to a file that includes Chinese characters started to fail. Apparently what we expect to be in the file is not correct.
> First write:
> Expect - "每個規則有一個例外。"
> Received - "每個規則有一個例外。"
> After append:
> Expect - "每個規則有一個例外。  除了這一個"
> Received - "每個規?  除了這一個"
> See environment section for the full test case.
> The root cause of the problem is that the FileWriter.write method returns the wrong number of bytes written for multi-byte language strings like Chinese characters.

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