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Diffstat (limited to 'include/lldb/Core/ConstString.h')
| -rw-r--r-- | include/lldb/Core/ConstString.h | 507 |
1 files changed, 507 insertions, 0 deletions
diff --git a/include/lldb/Core/ConstString.h b/include/lldb/Core/ConstString.h new file mode 100644 index 0000000..e692d3b --- /dev/null +++ b/include/lldb/Core/ConstString.h @@ -0,0 +1,507 @@ +//===-- 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_ +#if defined(__cplusplus) + +#include <assert.h> + +#include "lldb/lldb-private.h" +#include "llvm/ADT/StringRef.h" + + +namespace lldb_private { + +//---------------------------------------------------------------------- +/// @class ConstString ConstString.h "lldb/Core/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 (NULL) + { + } + + + //------------------------------------------------------------------ + /// 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 stirng, 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 () + { + } + + + //---------------------------------------------------------------------- + /// 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. + //------------------------------------------------------------------ + 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 NULL, then NULL 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 = NULL) const + { + if (m_string == NULL) + return value_if_empty; + return 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 NULL if the string is not + /// valid. So this function is a direct accessor to the string + /// pointer value. + /// + /// @return + /// Returns NULL 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 = NULL; + } + + //------------------------------------------------------------------ + /// 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 + /// comparision. 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. + /// + /// @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); + + //------------------------------------------------------------------ + /// 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 NULL, 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 NULL, nothing + /// will be output to the stream. + //------------------------------------------------------------------ + void + Dump (Stream *s, const char *value_if_empty = NULL) 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 == NULL || 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 sybmols 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 sybmols 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 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 + +#endif // #if defined(__cplusplus) +#endif // liblldb_ConstString_h_ |
