Chromium入坑之旅：base库之Files文件操作学习_base::filepath

一、base::FilePath

base::FilePath path = base::FilePath(L"C:\T.txt");
FilePath AddExtension(StringPieceType extension) ;//增加扩展名
path. AddExtension(L"ZIP"); // C:\T.txt.RAR

二、base::File

base/files/file.h
base::File file = base::File(const FilePath& path, uint32_t flags);
flags取值（可以用 “|”）

enum Flags {
    FLAG_OPEN = 1 << 0,                  // Opens a file, only if it exists.
    FLAG_CREATE = 1 << 1,                // Creates a new file, only if it does not already exist.
    FLAG_OPEN_ALWAYS = 1 << 2,           // May create a new file.
    FLAG_CREATE_ALWAYS = 1 << 3,         // May overwrite an old file.
    FLAG_OPEN_TRUNCATED = 1 << 4,        // Opens a file and truncates it, only if it exists.
    FLAG_READ = 1 << 5,
    FLAG_WRITE = 1 << 6,
    FLAG_APPEND = 1 << 7,
    FLAG_EXCLUSIVE_READ = 1 << 8,        // EXCLUSIVE is opposite of Windows SHARE.
    FLAG_EXCLUSIVE_WRITE = 1 << 9,
    FLAG_ASYNC = 1 << 10,
    FLAG_TEMPORARY = 1 << 11,            // Used on Windows only.
    FLAG_HIDDEN = 1 << 12,               // Used on Windows only.
    FLAG_DELETE_ON_CLOSE = 1 << 13,
    FLAG_WRITE_ATTRIBUTES = 1 << 14,     // Used on Windows only.
    FLAG_SHARE_DELETE = 1 << 15,         // Used on Windows only.
    FLAG_TERMINAL_DEVICE = 1 << 16,      // Serial port flags.
    FLAG_BACKUP_SEMANTICS = 1 << 17,     // Used on Windows only.
    FLAG_EXECUTE = 1 << 18,              // Used on Windows only.
    FLAG_SEQUENTIAL_SCAN = 1 << 19,      // Used on Windows only.
    FLAG_CAN_DELETE_ON_CLOSE = 1 << 20,  // Requests permission to delete a file via DeleteOnClose() (Windows only). See DeleteOnClose() for details.
  };
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文件打开 :（FLAG_OPEN）
文件打开并读取 :（FLAG_OPEN |FLAG_READ）
文件关闭后自动删除 :（FLAG_OPEN |FLAG_READ|FLAG_DELETE_ON_CLOSE）
文件手动选择关闭后是否删除 :（FLAG_OPEN |FLAG_READ|FLAG_CAN_DELETE_ON_CLOSE）
Close()之前设置DeleteOnClose(bool delete_on_close);
delete_on_close=true；// 关闭后删除
delete_on_close=false；// 关闭后不删除
Close();不需要主动调用，在File类的析构函数已调用改方法。

三、base::PathExists

base/files/file_util.h
bool PathExists(const FilePath& path)；//判断某个文件夹是否存在，不存在返回false，存在返回ture

四、base::CreateDirectory

base/files/file_util.h
创建一个文件夹目录

 bool CreateDirectory(const FilePath& full_path)；
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full_path = base::FilePath(L"C:\\123\\456\\"); // c:\123\456\
  CreateDirectory(full_path);//在c盘下创建123文件夹，并在123文件夹下创建456文件夹
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去掉后面的“\”,效果一样

full_path = base::FilePath(L"C:\\123\\456"); // c:\123\456
  CreateDirectory(full_path);//在c盘下创建123文件夹，并在123文件夹下创建456文件夹
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五、base::MakeAbsoluteFilePath

FilePath MakeAbsoluteFilePath(const FilePath& input);// 将相对路径转换为绝对路径
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base::MakeAbsoluteFilePath(base::FilePath(L"\\angledata\\"))；
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程序在D盘123目录运行 返回 D:\angledata
程序在C盘456目录运行 返回 C:\angledata\

base::ComputeDirectorySize

int64_t ComputeDirectorySize(const FilePath& root_path);// 返回给定路径目录大小
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base::ComputeDirectorySize(base::FilePath(L"C:\123\"))

base::DeleteFile

bool DeleteFile(const FilePath& path, bool recursive);
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如果path为目录，则 recursive 必须等于 true，不然无法删除文件夹。
如果path为文件，则 recursive 是否为true，都不会删除同目录下的其他文件和目录。

base::DeleteFileRecursively

bool DeleteFileRecursively(const FilePath& path); 
//等价于
bool DeleteFile(const FilePath& path, true);
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base::DeleteFileAfterReboot

bool DeleteFileAfterReboot(const FilePath& path);
//重启后删除文件，文件或目录必须位于"TMP" 文件下，目录必须为空

base::Move

bool Move(const FilePath& from_path, const FilePath& to_path);
from_path 可以是文件或者目录；
to_path 必须是目录；