Chromium Base库中常用的功能

按模块划分

String

base/strings/string_util.h

// Removes characters in |trim_chars| from the beginning and end of |input|.
// The 8-bit version only works on 8-bit characters, not UTF-8. Returns true if
// any characters were removed.
//
// It is safe to use the same variable for both |input| and |output| (this is
// the normal usage to trim in-place).
BASE_EXPORT bool TrimString(StringPiece16 input,
                            StringPiece16 trim_chars,
                            std::u16string* output);

去除首尾或首或尾指定子串。

相比folly::trim 易用性更好。

// Replaces characters in |replace_chars| from anywhere in |input| with
// |replace_with|.  Each character in |replace_chars| will be replaced with
// the |replace_with| string.  Returns true if any characters were replaced.
// |replace_chars| must be null-terminated.
// NOTE: Safe to use the same variable for both |input| and |output|.
BASE_EXPORT bool ReplaceChars(StringPiece16 input,
                              StringPiece16 replace_chars,
                              StringPiece16 replace_with,
                              std::u16string* output);

替换字符串中的指定子串。

// Converts the given string to it's ASCII-lowercase equivalent.
BASE_EXPORT std::string ToLowerASCII(StringPiece str);
BASE_EXPORT std::u16string ToLowerASCII(StringPiece16 str);
 
// Converts the given string to it's ASCII-uppercase equivalent.
BASE_EXPORT std::string ToUpperASCII(StringPiece str);
BASE_EXPORT std::u16string ToUpperASCII(StringPiece16 str);

大小写转换。

// Indicates case sensitivity of comparisons. Only ASCII case insensitivity
// is supported. Full Unicode case-insensitive conversions would need to go in
// base/i18n so it can use ICU.
//
// If you need to do Unicode-aware case-insensitive StartsWith/EndsWith, it's
// best to call base::i18n::ToLower() or base::i18n::FoldCase() (see
// base/i18n/case_conversion.h for usage advice) on the arguments, and then use
// the results to a case-sensitive comparison.
enum class CompareCase {
  SENSITIVE,
  INSENSITIVE_ASCII,
};
 
BASE_EXPORT bool StartsWith(
    StringPiece str,
    StringPiece search_for,
    CompareCase case_sensitivity = CompareCase::SENSITIVE);
BASE_EXPORT bool EndsWith(
    StringPiece str,
    StringPiece search_for,
    CompareCase case_sensitivity = CompareCase::SENSITIVE);

判断字符串是否以某子串起始或结束。

base/strings/string_split.h

// Split the given string on ANY of the given separators, returning copies of
// the result.
//
// Note this is inverse of JoinString() defined in string_util.h.
//
// To split on either commas or semicolons, keeping all whitespace:
//
//   std::vector<std::string> tokens = base::SplitString(
//       input, ",;", base::KEEP_WHITESPACE, base::SPLIT_WANT_ALL);
[[nodiscard]] BASE_EXPORT std::vector<std::string> SplitString(
    StringPiece input,
    StringPiece separators,
    WhitespaceHandling whitespace,
    SplitResult result_type);

分割字符串进vector。

CommandLine

base/command_line.h

// This class works with command lines: building and parsing.
// Arguments with prefixes ('--', '-', and on Windows, '/') are switches.
// Switches will precede all other arguments without switch prefixes.
// Switches can optionally have values, delimited by '=', e.g., "-switch=value".
// If a switch is specified multiple times, only the last value is used.
// An argument of "--" will terminate switch parsing during initialization,
// interpreting subsequent tokens as non-switch arguments, regardless of prefix.
 
class CommandLine
 
// Returns true if this command line contains the given switch.
  // Switch names must be lowercase.
  // The second override provides an optimized version to avoid inlining codegen
  // at every callsite to find the length of the constant and construct a
  // StringPiece.
  bool HasSwitch(StringPiece switch_string) const;
  bool HasSwitch(const char switch_constant[]) const;
 
 // Returns the value associated with the given switch. If the switch has no
  // value or isn't present, this method returns the empty string.
  // Switch names must be lowercase.
  std::string GetSwitchValueASCII(StringPiece switch_string) const;
  FilePath GetSwitchValuePath(StringPiece switch_string) const;
  StringType GetSwitchValueNative(StringPiece switch_string) const;

解析命令行。

Process

base/process/launch.h

// Launch a process via the command line |cmdline|.
// See the documentation of LaunchOptions for details on |options|.
//
// Returns a valid Process upon success.
 
BASE_EXPORT Process LaunchProcess(const CommandLine& cmdline,
                                  const LaunchOptions& options);

运行进程。

base/process/process.h

// Provides a move-only encapsulation of a process.
//
// This object is not tied to the lifetime of the underlying process: the
// process may be killed and this object may still around, and it will still
// claim to be valid. The actual behavior in that case is OS dependent like so:
//
// Windows: The underlying ProcessHandle will be valid after the process dies
// and can be used to gather some information about that process, but most
// methods will obviously fail.
 
class Process 

获取进程信息。

base/hash/md5.h

// Returns the MD5 (in hexadecimal) of a string.
BASE_EXPORT std::string MD5String(const StringPiece& str);

生成MD5字符串。

base/files

文件相关系列操作。