Question

我创建了一个函数，帮助查找NSString数组中的重复文件（数组包含文件路径）

这是我的功能：

-(NSMutableArray *)compareWithList:(NSMutableArray*)fileCompareList // list of file from which we need to find the duplicates of the target
                          fileData:(NSData*)_fileData // contains target file data bytes
                        fileLength:(UInt32) _fileLenght // contains size of target file
{
    // result list of the (duplcate)files
    NSMutableArray* fileList = [[NSMutableArray alloc]init];

    // flag to check if the path is a folder
    BOOL isDir;

    //stores the size of the file that is being itrated
    UInt32 size = 0;
    //stores the byte data of the file that is being itrated
    NSData *bytes = nil;

    //itrating the files in the list one by one in order find the duplicate
    for (NSString* sPath in fileCompareList) {
        //checking if the file already exists in the result list
        if ([fileList indexOfObject:sPath] == NSNotFound)
        {
            //getting the size of the file
            UInt32 size = [sysHelp getSizeOfFile:sPath];
            //if the size matches of the target file and the itrated file then go inside
            if(size == _fileLenght)
            {
                //get the bytes of the file being itrated
                bytes = [[NSData alloc] initWithContentsOfFile:sPath];

                //if the bytes matches then add the itrated file into the result list
                if([bytes isEqualToData:_fileData])
                {
                    [fileList addObject:sPath];
                }
                //remove the itrated file data from the array
                bytes = nil;
            }
        }

    }

    return fileList;
}

这里的问题是因为功能内存使用率变高，如下面的屏幕截图所示：

之前的

后

一段时间后

请注意;我正在使用ARC

我如何称呼这个功能？这是：

NSMutableArray* allFilesOfSystem =[[NSMutableArray alloc] init];
allFilesOfSystem = self AllFilesOfDesktopAndSubDirectores];

NSMutableArray* FinalResultArray = [[NSMutableArray alloc] init];

for (int i = 0; i < [allFilesOfSystem count]; i++) {

        NSString* filePath = [allFilesOfSystem objectAtIndex:i];

        //file to byte array
        NSData *bytes = [[NSData alloc] initWithContentsOfFile:filePath];

        //file size
        UInt32 size = [sysHelp getSizeOfFile:filePath];

        [FinalResultArray addObjectsFromArray:[self compareWithList:allFilesOfSystem fileData:bytes fileLength:size]]

}

Answer 1

请在@ autoreleasepool中移动您的所有陈述，如果有帮助请告诉我。以下是代码

-(NSMutableArray *)compareWithList:(NSMutableArray*)fileCompareList // list of file from which we need to find the duplicates of the target
                          fileData:(NSData*)_fileData // contains target file data bytes
                        fileLength:(UInt32) _fileLenght // contains size of target file
{
  // result list of the (duplcate)files
  NSMutableArray* fileList = [[NSMutableArray alloc] init];

  @autoreleasepool {
    // flag to check if the path is a folder
    BOOL isDir;

    //stores the size of the file that is being itrated
    UInt32 size = 0;
    //stores the byte data of the file that is being itrated
    NSData *bytes = nil;

    //itrating the files in the list one by one in order find the duplicate
    for (NSString* sPath in fileCompareList) {
      //checking if the file already exists in the result list
      if ([fileList indexOfObject:sPath] == NSNotFound)
      {
        //getting the size of the file
        UInt32 size = [sysHelp getSizeOfFile:sPath];
        //if the size matches of the target file and the itrated file then go inside
        if(size == _fileLenght)
        {
          //get the bytes of the file being itrated
          bytes = [[NSData alloc] initWithContentsOfFile:sPath];

          //if the bytes matches then add the itrated file into the result list
          if([bytes isEqualToData:_fileData])
          {
            [fileList addObject:sPath];
          }
          //remove the itrated file data from the array
          bytes = nil;
        }
      }

    }
  }
  return fileList;
}

编辑：说明

有两种方法可以放弃对象的所有权。一个是释放，另一个是自动释放。如果对对象调用release并且如果对象的保留计数变为它会立即释放，但是如果自动释放对象，则释放/排出自动释放池后将发送释放消息，即延迟释放。让我们举一个例子。

- (void)testMemoryInARC1 {
  NSData *data = [[NSData alloc] initWithContentsOfFile:@"myfile.mp3"]; // reatin count is 1
  //used this data an after few statements
  //statement 1
  // ..


  //at the end of data varibale scope in this case it's the end of method
  //ARC will insert the release call
  // [data rlease]; //wchich releases the memory
}


- (void)testMemoryInARC2 {
  NSData *data = [NSData dataWithContentsOfFile:@"myfile.mp3"]; // this method returns the autorelase object
  //used this data an after few statements
  //statement 1
  // ..


  //at the end of data varibale scope in this case it's the end of method
  //ARC will NOT insert the release call since that was autoreleased object
  //hence no release call
}

所以问题什么时候会被释放？
ARS说，＆＃34;好的问题，它将在自动发布池结束（发布）后发布＆＃34;。

自动发布池何时结束？
ARC说，＆＃34;只要检查你在哪里创建了自动释放池，如果你还没有创建它，那么main.m文件中有一个主要的自动释放池＆＃34;

这意味着当main方法完成时会释放所有自动释放对象，这对程序结束有什么帮助？
ARC说，＆＃34;再好的问题！ Cocoa库在开发过程中使用了自动释放池，如果你还没有使用它，那么先生，你的问题不是我的。＆＃34;

应用程序不释放内存，每次内存使用量增加一倍

1 个答案:

编辑：说明

About Memory Management