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Diffstat (limited to 'include/lldb/Utility/ConstString.h')
| -rw-r--r-- | include/lldb/Utility/ConstString.h | 490 |
1 files changed, 490 insertions, 0 deletions
diff --git a/include/lldb/Utility/ConstString.h b/include/lldb/Utility/ConstString.h new file mode 100644 index 000000000000..fbf1a9bf536e --- /dev/null +++ b/include/lldb/Utility/ConstString.h @@ -0,0 +1,490 @@ +//===-- ConstString.h -------------------------------------------*- C++ -*-===// +// +// The LLVM Compiler Infrastructure +// +// This file is distributed under the University of Illinois Open Source +// License. See LICENSE.TXT for details. +// +//===----------------------------------------------------------------------===// + +#ifndef liblldb_ConstString_h_ +#define liblldb_ConstString_h_ + +#include "llvm/ADT/StringRef.h" +#include "llvm/Support/FormatVariadic.h" // for format_provider + +#include <stddef.h> // for size_t + +namespace lldb_private { +class Stream; +} +namespace llvm { +class raw_ostream; +} + +namespace lldb_private { + +//---------------------------------------------------------------------- +/// @class ConstString ConstString.h "lldb/Utility/ConstString.h" +/// @brief A uniqued constant string class. +/// +/// Provides an efficient way to store strings as uniqued strings. After +/// the strings are uniqued, finding strings that are equal to one +/// another is very fast as just the pointers need to be compared. It +/// also allows for many common strings from many different sources to +/// be shared to keep the memory footprint low. +/// +/// No reference counting is done on strings that are added to the +/// string pool, once strings are added they are in the string pool for +/// the life of the program. +//---------------------------------------------------------------------- +class ConstString { +public: + //------------------------------------------------------------------ + /// Default constructor + /// + /// Initializes the string to an empty string. + //------------------------------------------------------------------ + ConstString() : m_string(nullptr) {} + + //------------------------------------------------------------------ + /// Copy constructor + /// + /// Copies the string value in \a rhs into this object. + /// + /// @param[in] rhs + /// Another string object to copy. + //------------------------------------------------------------------ + ConstString(const ConstString &rhs) : m_string(rhs.m_string) {} + + explicit ConstString(const llvm::StringRef &s); + + //------------------------------------------------------------------ + /// Construct with C String value + /// + /// Constructs this object with a C string by looking to see if the + /// C string already exists in the global string pool. If it doesn't + /// exist, it is added to the string pool. + /// + /// @param[in] cstr + /// A NULL terminated C string to add to the string pool. + //------------------------------------------------------------------ + explicit ConstString(const char *cstr); + + //------------------------------------------------------------------ + /// Construct with C String value with max length + /// + /// Constructs this object with a C string with a length. If + /// \a max_cstr_len is greater than the actual length of the string, + /// the string length will be truncated. This allows substrings to + /// be created without the need to NULL terminate the string as it + /// is passed into this function. + /// + /// @param[in] cstr + /// A pointer to the first character in the C string. The C + /// string can be NULL terminated in a buffer that contains + /// more characters than the length of the string, or the + /// string can be part of another string and a new substring + /// can be created. + /// + /// @param[in] max_cstr_len + /// The max length of \a cstr. If the string length of \a cstr + /// is less than \a max_cstr_len, then the string will be + /// truncated. If the string length of \a cstr is greater than + /// \a max_cstr_len, then only max_cstr_len bytes will be used + /// from \a cstr. + //------------------------------------------------------------------ + explicit ConstString(const char *cstr, size_t max_cstr_len); + + //------------------------------------------------------------------ + /// Destructor + /// + /// Since constant string values are currently not reference counted, + /// there isn't much to do here. + //------------------------------------------------------------------ + ~ConstString() = default; + + //---------------------------------------------------------------------- + /// C string equality binary predicate function object for ConstString + /// objects. + //---------------------------------------------------------------------- + struct StringIsEqual { + //-------------------------------------------------------------- + /// C equality test. + /// + /// Two C strings are equal when they are contained in ConstString + /// objects when their pointer values are equal to each other. + /// + /// @return + /// Returns \b true if the C string in \a lhs is equal to + /// the C string value in \a rhs, \b false otherwise. + //-------------------------------------------------------------- + bool operator()(const char *lhs, const char *rhs) const { + return lhs == rhs; + } + }; + + //------------------------------------------------------------------ + /// Convert to bool operator. + /// + /// This allows code to check a ConstString object to see if it + /// contains a valid string using code such as: + /// + /// @code + /// ConstString str(...); + /// if (str) + /// { ... + /// @endcode + /// + /// @return + /// /b True this object contains a valid non-empty C string, \b + /// false otherwise. + //------------------------------------------------------------------ + explicit operator bool() const { return m_string && m_string[0]; } + + //------------------------------------------------------------------ + /// Assignment operator + /// + /// Assigns the string in this object with the value from \a rhs. + /// + /// @param[in] rhs + /// Another string object to copy into this object. + /// + /// @return + /// A const reference to this object. + //------------------------------------------------------------------ + const ConstString &operator=(const ConstString &rhs) { + m_string = rhs.m_string; + return *this; + } + + //------------------------------------------------------------------ + /// Equal to operator + /// + /// Returns true if this string is equal to the string in \a rhs. + /// This operation is very fast as it results in a pointer + /// comparison since all strings are in a uniqued in a global string + /// pool. + /// + /// @param[in] rhs + /// Another string object to compare this object to. + /// + /// @return + /// @li \b true if this object is equal to \a rhs. + /// @li \b false if this object is not equal to \a rhs. + //------------------------------------------------------------------ + bool operator==(const ConstString &rhs) const { + // We can do a pointer compare to compare these strings since they + // must come from the same pool in order to be equal. + return m_string == rhs.m_string; + } + + //------------------------------------------------------------------ + /// Not equal to operator + /// + /// Returns true if this string is not equal to the string in \a rhs. + /// This operation is very fast as it results in a pointer + /// comparison since all strings are in a uniqued in a global string + /// pool. + /// + /// @param[in] rhs + /// Another string object to compare this object to. + /// + /// @return + /// @li \b true if this object is not equal to \a rhs. + /// @li \b false if this object is equal to \a rhs. + //------------------------------------------------------------------ + bool operator!=(const ConstString &rhs) const { + return m_string != rhs.m_string; + } + + bool operator<(const ConstString &rhs) const; + + //------------------------------------------------------------------ + /// Get the string value as a C string. + /// + /// Get the value of the contained string as a NULL terminated C + /// string value. + /// + /// If \a value_if_empty is nullptr, then nullptr will be returned. + /// + /// @return + /// Returns \a value_if_empty if the string is empty, otherwise + /// the C string value contained in this object. + //------------------------------------------------------------------ + const char *AsCString(const char *value_if_empty = nullptr) const { + return (IsEmpty() ? value_if_empty : m_string); + } + + //------------------------------------------------------------------ + /// Get the string value as a llvm::StringRef + /// + /// @return + /// Returns a new llvm::StringRef object filled in with the + /// needed data. + //------------------------------------------------------------------ + llvm::StringRef GetStringRef() const { + return llvm::StringRef(m_string, GetLength()); + } + + //------------------------------------------------------------------ + /// Get the string value as a C string. + /// + /// Get the value of the contained string as a NULL terminated C + /// string value. Similar to the ConstString::AsCString() function, + /// yet this function will always return nullptr if the string is not + /// valid. So this function is a direct accessor to the string + /// pointer value. + /// + /// @return + /// Returns nullptr the string is invalid, otherwise the C string + /// value contained in this object. + //------------------------------------------------------------------ + const char *GetCString() const { return m_string; } + + //------------------------------------------------------------------ + /// Get the length in bytes of string value. + /// + /// The string pool stores the length of the string, so we can avoid + /// calling strlen() on the pointer value with this function. + /// + /// @return + /// Returns the number of bytes that this string occupies in + /// memory, not including the NULL termination byte. + //------------------------------------------------------------------ + size_t GetLength() const; + + //------------------------------------------------------------------ + /// Clear this object's state. + /// + /// Clear any contained string and reset the value to the an empty + /// string value. + //------------------------------------------------------------------ + void Clear() { m_string = nullptr; } + + //------------------------------------------------------------------ + /// Equal to operator + /// + /// Returns true if this string is equal to the string in \a rhs. + /// If case sensitive equality is tested, this operation is very + /// fast as it results in a pointer comparison since all strings + /// are in a uniqued in a global string pool. + /// + /// @param[in] rhs + /// The Left Hand Side const ConstString object reference. + /// + /// @param[in] rhs + /// The Right Hand Side const ConstString object reference. + /// + /// @param[in] case_sensitive + /// Case sensitivity. If true, case sensitive equality + /// will be tested, otherwise character case will be ignored + /// + /// @return + /// @li \b true if this object is equal to \a rhs. + /// @li \b false if this object is not equal to \a rhs. + //------------------------------------------------------------------ + static bool Equals(const ConstString &lhs, const ConstString &rhs, + const bool case_sensitive = true); + + //------------------------------------------------------------------ + /// Compare two string objects. + /// + /// Compares the C string values contained in \a lhs and \a rhs and + /// returns an integer result. + /// + /// NOTE: only call this function when you want a true string + /// comparison. If you want string equality use the, use the == + /// operator as it is much more efficient. Also if you want string + /// inequality, use the != operator for the same reasons. + /// + /// @param[in] lhs + /// The Left Hand Side const ConstString object reference. + /// + /// @param[in] rhs + /// The Right Hand Side const ConstString object reference. + /// + /// @param[in] case_sensitive + /// Case sensitivity of compare. If true, case sensitive compare + /// will be performed, otherwise character case will be ignored + /// + /// @return + /// @li -1 if lhs < rhs + /// @li 0 if lhs == rhs + /// @li 1 if lhs > rhs + //------------------------------------------------------------------ + static int Compare(const ConstString &lhs, const ConstString &rhs, + const bool case_sensitive = true); + + //------------------------------------------------------------------ + /// Dump the object description to a stream. + /// + /// Dump the string value to the stream \a s. If the contained string + /// is empty, print \a value_if_empty to the stream instead. If + /// \a value_if_empty is nullptr, then nothing will be dumped to the + /// stream. + /// + /// @param[in] s + /// The stream that will be used to dump the object description. + /// + /// @param[in] value_if_empty + /// The value to dump if the string is empty. If nullptr, nothing + /// will be output to the stream. + //------------------------------------------------------------------ + void Dump(Stream *s, const char *value_if_empty = nullptr) const; + + //------------------------------------------------------------------ + /// Dump the object debug description to a stream. + /// + /// @param[in] s + /// The stream that will be used to dump the object description. + //------------------------------------------------------------------ + void DumpDebug(Stream *s) const; + + //------------------------------------------------------------------ + /// Test for empty string. + /// + /// @return + /// @li \b true if the contained string is empty. + /// @li \b false if the contained string is not empty. + //------------------------------------------------------------------ + bool IsEmpty() const { return m_string == nullptr || m_string[0] == '\0'; } + + //------------------------------------------------------------------ + /// Set the C string value. + /// + /// Set the string value in the object by uniquing the \a cstr + /// string value in our global string pool. + /// + /// If the C string already exists in the global string pool, it + /// finds the current entry and returns the existing value. If it + /// doesn't exist, it is added to the string pool. + /// + /// @param[in] cstr + /// A NULL terminated C string to add to the string pool. + //------------------------------------------------------------------ + void SetCString(const char *cstr); + + void SetString(const llvm::StringRef &s); + + //------------------------------------------------------------------ + /// Set the C string value and its mangled counterpart. + /// + /// Object files and debug symbols often use mangled string to + /// represent the linkage name for a symbol, function or global. + /// The string pool can efficiently store these values and their + /// counterparts so when we run into another instance of a mangled + /// name, we can avoid calling the name demangler over and over on + /// the same strings and then trying to unique them. + /// + /// @param[in] demangled + /// The demangled C string to correlate with the \a mangled + /// name. + /// + /// @param[in] mangled + /// The already uniqued mangled ConstString to correlate the + /// soon to be uniqued version of \a demangled. + //------------------------------------------------------------------ + void SetCStringWithMangledCounterpart(const char *demangled, + const ConstString &mangled); + + //------------------------------------------------------------------ + /// Retrieve the mangled or demangled counterpart for a mangled + /// or demangled ConstString. + /// + /// Object files and debug symbols often use mangled string to + /// represent the linkage name for a symbol, function or global. + /// The string pool can efficiently store these values and their + /// counterparts so when we run into another instance of a mangled + /// name, we can avoid calling the name demangler over and over on + /// the same strings and then trying to unique them. + /// + /// @param[in] counterpart + /// A reference to a ConstString object that might get filled in + /// with the demangled/mangled counterpart. + /// + /// @return + /// /b True if \a counterpart was filled in with the counterpart + /// /b false otherwise. + //------------------------------------------------------------------ + bool GetMangledCounterpart(ConstString &counterpart) const; + + //------------------------------------------------------------------ + /// Set the C string value with length. + /// + /// Set the string value in the object by uniquing \a cstr_len bytes + /// starting at the \a cstr string value in our global string pool. + /// If trim is true, then \a cstr_len indicates a maximum length of + /// the CString and if the actual length of the string is less, then + /// it will be trimmed. + /// + /// If the C string already exists in the global string pool, it + /// finds the current entry and returns the existing value. If it + /// doesn't exist, it is added to the string pool. + /// + /// @param[in] cstr + /// A NULL terminated C string to add to the string pool. + /// + /// @param[in] cstr_len + /// The maximum length of the C string. + //------------------------------------------------------------------ + void SetCStringWithLength(const char *cstr, size_t cstr_len); + + //------------------------------------------------------------------ + /// Set the C string value with the minimum length between + /// \a fixed_cstr_len and the actual length of the C string. This + /// can be used for data structures that have a fixed length to + /// store a C string where the string might not be NULL terminated + /// if the string takes the entire buffer. + //------------------------------------------------------------------ + void SetTrimmedCStringWithLength(const char *cstr, size_t fixed_cstr_len); + + //------------------------------------------------------------------ + /// Get the memory cost of this object. + /// + /// Return the size in bytes that this object takes in memory. This + /// returns the size in bytes of this object, which does not include + /// any the shared string values it may refer to. + /// + /// @return + /// The number of bytes that this object occupies in memory. + /// + /// @see ConstString::StaticMemorySize () + //------------------------------------------------------------------ + size_t MemorySize() const { return sizeof(ConstString); } + + //------------------------------------------------------------------ + /// Get the size in bytes of the current global string pool. + /// + /// Reports the size in bytes of all shared C string values, + /// containers and any other values as a byte size for the + /// entire string pool. + /// + /// @return + /// The number of bytes that the global string pool occupies + /// in memory. + //------------------------------------------------------------------ + static size_t StaticMemorySize(); + +protected: + //------------------------------------------------------------------ + // Member variables + //------------------------------------------------------------------ + const char *m_string; +}; + +//------------------------------------------------------------------ +/// Stream the string value \a str to the stream \a s +//------------------------------------------------------------------ +Stream &operator<<(Stream &s, const ConstString &str); + +} // namespace lldb_private + +namespace llvm { +template <> struct format_provider<lldb_private::ConstString> { + static void format(const lldb_private::ConstString &CS, llvm::raw_ostream &OS, + llvm::StringRef Options); +}; +} + +#endif // liblldb_ConstString_h_ |