Add base to the repository.

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@8 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 382 insertions, 0 deletions

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+// Copyright 2008, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//    * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//    * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//    * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// This file specifies a recursive data storage class called Value
+// intended for storing setting and other persistable data.
+// It includes the ability to specify (recursive) lists and dictionaries, so
+// it's fairly expressive.  However, the API is optimized for the common case,
+// namely storing a hierarchical tree of simple values.  Given a
+// DictionaryValue root, you can easily do things like:
+//
+// root->SetString(L"global.pages.homepage", L"http://goateleporter.com");
+// std::wstring homepage = L"http://google.com";  // default/fallback value
+// root->GetString(L"global.pages.homepage", &homepage);
+//
+// where "global" and "pages" are also DictionaryValues, and "homepage"
+// is a string setting.  If some elements of the path didn't exist yet,
+// the SetString() method would create the missing elements and attach them
+// to root before attaching the homepage value.
+
+#ifndef CHROME_COMMON_VALUES_H__
+#define CHROME_COMMON_VALUES_H__
+
+#include <iterator>
+#include <map>
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+
+class Value;
+class FundamentalValue;
+class StringValue;
+class BinaryValue;
+class DictionaryValue;
+class ListValue;
+
+typedef std::vector<Value*> ValueVector;
+typedef std::map<std::wstring, Value*> ValueMap;
+
+// The Value class is the base class for Values.  A Value can be
+// instantiated via the Create*Value() factory methods, or by directly
+// creating instances of the subclasses.
+class Value {
+ public:
+  virtual ~Value();
+
+  // Convenience methods for creating Value objects for various
+  // kinds of values without thinking about which class implements them.
+  // These can always be expected to return a valid Value*.
+  static Value* CreateNullValue();
+  static Value* CreateBooleanValue(bool in_value);
+  static Value* CreateIntegerValue(int in_value);
+  static Value* CreateRealValue(double in_value);
+  static Value* CreateStringValue(const std::wstring& in_value);
+
+  // This one can return NULL if the input isn't valid.  If the return value
+  // is non-null, the new object has taken ownership of the buffer pointer.
+  static BinaryValue* CreateBinaryValue(char* buffer, size_t size);
+
+  typedef enum {
+    TYPE_NULL = 0,
+    TYPE_BOOLEAN,
+    TYPE_INTEGER,
+    TYPE_REAL,
+    TYPE_STRING,
+    TYPE_BINARY,
+    TYPE_DICTIONARY,
+    TYPE_LIST
+  } ValueType;
+
+  // Returns the type of the value stored by the current Value object.
+  // Each type will be implemented by only one subclass of Value, so it's
+  // safe to use the ValueType to determine whether you can cast from
+  // Value* to (Implementing Class)*.  Also, a Value object never changes
+  // its type after construction.
+  ValueType GetType() const { return type_; }
+
+  // Returns true if the current object represents a given type.
+  bool IsType(ValueType type) const { return type == type_; }
+
+  // These methods allow the convenient retrieval of settings.
+  // If the current setting object can be converted into the given type,
+  // the value is returned through the "value" parameter and true is returned;
+  // otherwise, false is returned and "value" is unchanged.
+  virtual bool GetAsBoolean(bool* out_value) const;
+  virtual bool GetAsInteger(int* out_value) const;
+  virtual bool GetAsReal(double* out_value) const;
+  virtual bool GetAsString(std::wstring* out_value) const;
+
+  // This creates a deep copy of the entire Value tree, and returns a pointer
+  // to the copy.  The caller gets ownership of the copy, of course.
+  virtual Value* DeepCopy() const;
+
+  // Compares if two Value objects have equal contents.
+  virtual bool Equals(const Value* other) const;
+
+ protected:
+  // This isn't safe for end-users (they should use the Create*Value()
+  // static methods above), but it's useful for subclasses.
+  Value(ValueType type) : type_(type) {}
+
+ private:
+  DISALLOW_EVIL_CONSTRUCTORS(Value);
+  Value();
+
+  ValueType type_;
+};
+
+// FundamentalValue represents the simple fundamental types of values.
+class FundamentalValue : public Value {
+ public:
+  FundamentalValue(bool in_value)
+    : Value(TYPE_BOOLEAN), boolean_value_(in_value) {}
+  FundamentalValue(int in_value)
+    : Value(TYPE_INTEGER), integer_value_(in_value) {}
+  FundamentalValue(double in_value)
+    : Value(TYPE_REAL), real_value_(in_value) {}
+  ~FundamentalValue();
+
+  // Subclassed methods
+  virtual bool GetAsBoolean(bool* out_value) const;
+  virtual bool GetAsInteger(int* out_value) const;
+  virtual bool GetAsReal(double* out_value) const;
+  virtual Value* DeepCopy() const;
+  virtual bool Equals(const Value* other) const;
+
+ private:
+  DISALLOW_EVIL_CONSTRUCTORS(FundamentalValue);
+
+  union {
+    bool boolean_value_;
+    int integer_value_;
+    double real_value_;
+  };
+};
+
+class StringValue : public Value {
+ public:
+  StringValue(const std::wstring& in_value)
+    : Value(TYPE_STRING), value_(in_value) {}
+  ~StringValue();
+
+  // Subclassed methods
+  bool GetAsString(std::wstring* out_value) const;
+  Value* DeepCopy() const;
+  virtual bool Equals(const Value* other) const;
+
+ private:
+  DISALLOW_EVIL_CONSTRUCTORS(StringValue);
+
+  std::wstring value_;
+};
+
+class BinaryValue: public Value {
+public:
+  // Creates a Value to represent a binary buffer.  The new object takes
+  // ownership of the pointer passed in, if successful.
+  // Returns NULL if buffer is NULL.
+  static BinaryValue* Create(char* buffer, size_t size);
+
+  // For situations where you want to keep ownership of your buffer, this
+  // factory method creates a new BinaryValue by copying the contents of the
+  // buffer that's passed in.
+  // Returns NULL if buffer is NULL.
+  static BinaryValue* CreateWithCopiedBuffer(char* buffer, size_t size);
+
+  BinaryValue::~BinaryValue();
+
+  // Subclassed methods
+  Value* DeepCopy() const;
+  virtual bool Equals(const Value* other) const;
+
+  size_t GetSize() const { return size_; }
+  char* GetBuffer() { return buffer_; }
+
+private:
+  DISALLOW_EVIL_CONSTRUCTORS(BinaryValue);
+
+  // Constructor is private so that only objects with valid buffer pointers
+  // and size values can be created.
+  BinaryValue::BinaryValue(char* buffer, size_t size);
+
+  char* buffer_;
+  size_t size_;
+};
+
+class DictionaryValue : public Value {
+ public:
+  DictionaryValue() : Value(TYPE_DICTIONARY) {}
+  ~DictionaryValue();
+
+  // Subclassed methods
+  Value* DeepCopy() const;
+  virtual bool Equals(const Value* other) const;
+
+  // Returns true if the current dictionary has a value for the given key.
+  bool DictionaryValue::HasKey(const std::wstring& key);
+
+  // Clears any current contents of this dictionary.
+  void DictionaryValue::Clear();
+
+  // Sets the Value associated with the given path starting from this object.
+  // A path has the form "<key>" or "<key>.<key>.[...]", where "." indexes
+  // into the next DictionaryValue down.  Obviously, "." can't be used
+  // within a key, but there are no other restrictions on keys.
+  // If the key at any step of the way doesn't exist, or exists but isn't
+  // a DictionaryValue, a new DictionaryValue will be created and attached
+  // to the path in that location.
+  // Note that the dictionary takes ownership of the value
+  // referenced by in_value.
+  bool Set(const std::wstring& path, Value* in_value);
+
+  // Convenience forms of Set().  These methods will replace any existing
+  // value at that path, even if it has a different type.
+  bool SetBoolean(const std::wstring& path, bool in_value);
+  bool SetInteger(const std::wstring& path, int in_value);
+  bool SetReal(const std::wstring& path, double in_value);
+  bool SetString(const std::wstring& path, const std::wstring& in_value);
+
+  // Gets the Value associated with the given path starting from this object.
+  // A path has the form "<key>" or "<key>.<key>.[...]", where "." indexes
+  // into the next DictionaryValue down.  If the path can be resolved
+  // successfully, the value for the last key in the path will be returned
+  // through the "value" parameter, and the function will return true.
+  // Otherwise, it will return false and "value" will be untouched.
+  // Note that the dictionary always owns the value that's returned.
+  bool Get(const std::wstring& path, Value** out_value) const;
+
+  // These are convenience forms of Get().  The value will be retrieved
+  // and the return value will be true if the path is valid and the value at
+  // the end of the path can be returned in the form specified.
+  bool GetBoolean(const std::wstring& path, bool* out_value) const;
+  bool GetInteger(const std::wstring& path, int* out_value) const;
+  bool GetReal(const std::wstring& path, double* out_value) const;
+  bool GetString(const std::wstring& path, std::wstring* out_value) const;
+  bool GetBinary(const std::wstring& path, BinaryValue** out_value) const;
+  bool GetDictionary(const std::wstring& path,
+                     DictionaryValue** out_value) const;
+  bool GetList(const std::wstring& path, ListValue** out_value) const;
+
+  // Removes the Value with the specified path from this dictionary (or one
+  // of its child dictionaries, if the path is more than just a local key).
+  // If |out_value| is non-NULL, the removed Value AND ITS OWNERSHIP will be
+  // passed out via out_value.  If |out_value| is NULL, the removed value will
+  // be deleted.  This method returns true if |path| is a valid path; otherwise
+  // it will return false and the DictionaryValue object will be unchanged.
+  bool Remove(const std::wstring& path, Value** out_value);
+
+  // This class provides an iterator for the keys in the dictionary.
+  // It can't be used to modify the dictionary.
+  class key_iterator
+    : private std::iterator<std::input_iterator_tag, const std::wstring> {
+  public:
+    key_iterator(ValueMap::const_iterator itr) { itr_ = itr; }
+    key_iterator operator++() { ++itr_; return *this; }
+    const std::wstring& operator*() { return itr_->first; }
+    bool operator!=(const key_iterator& other) { return itr_ != other.itr_; }
+    bool operator==(const key_iterator& other) { return itr_ == other.itr_; }
+
+  private:
+    ValueMap::const_iterator itr_;
+  };
+
+  key_iterator begin_keys() const { return key_iterator(dictionary_.begin()); }
+  key_iterator end_keys() const { return key_iterator(dictionary_.end()); }
+
+ private:
+  DISALLOW_EVIL_CONSTRUCTORS(DictionaryValue);
+
+  // Associates the value |in_value| with the |key|.  This method should be
+  // used instead of "dictionary_[key] = foo" so that any previous value can
+  // be properly deleted.
+  void SetInCurrentNode(const std::wstring& key, Value* in_value);
+
+  ValueMap dictionary_;
+};
+
+// This type of Value represents a list of other Value values.
+// TODO(jhughes): Flesh this out.
+class ListValue : public Value {
+ public:
+  ListValue() : Value(TYPE_LIST) {}
+  ~ListValue();
+
+  // Subclassed methods
+  Value* DeepCopy() const;
+  virtual bool Equals(const Value* other) const;
+
+  // Clears the contents of this ListValue
+  void Clear();
+
+  // Returns the number of Values in this list.
+  size_t GetSize() const { return list_.size(); }
+
+  // Sets the list item at the given index to be the Value specified by
+  // the value given.  If the index beyond the current end of the list, null
+  // Values will be used to pad out the list.
+  // Returns true if successful, or false if the index was negative or
+  // the value is a null pointer.
+  bool Set(size_t index, Value* in_value);
+
+  // Gets the Value at the given index.  Modifies value (and returns true)
+  // only if the index falls within the current list range.
+  // Note that the list always owns the Value passed out via out_value.
+  bool Get(size_t index, Value** out_value) const;
+
+  // Convenience forms of Get().  Modifies value (and returns true) only if
+  // the index is valid and the Value at that index can be returned in
+  // the specified form.
+  bool GetDictionary(size_t index, DictionaryValue** out_value) const;
+
+  // Removes the Value with the specified index from this list.
+  // If |out_value| is non-NULL, the removed Value AND ITS OWNERSHIP will be
+  // passed out via out_value.  If |out_value| is NULL, the removed value will
+  // be deleted.  This method returns true if |index| is valid; otherwise
+  // it will return false and the ListValue object will be unchanged.
+  bool Remove(size_t index, Value** out_value);
+
+  // Appends a Value to the end of the list.
+  void Append(Value* in_value);
+
+  // Iteration
+  typedef ValueVector::iterator iterator;
+  typedef ValueVector::const_iterator const_iterator;
+
+  ListValue::iterator begin() { return list_.begin(); }
+  ListValue::iterator end() { return list_.end(); }
+
+  ListValue::const_iterator begin() const { return list_.begin(); }
+  ListValue::const_iterator end() const { return list_.end(); }
+
+  ListValue::iterator Erase(iterator item) {
+    return list_.erase(item);
+  }
+
+ private:
+  DISALLOW_EVIL_CONSTRUCTORS(ListValue);
+
+  ValueVector list_;
+};
+
+// This interface is implemented by classes that know how to serialize and
+// deserialize Value objects.
+class ValueSerializer {
+ public:
+  virtual bool Serialize(const Value& root) = 0;
+
+  // This method deserializes the subclass-specific format into a Value object.
+  // The method should return true if and only if the root parameter is set
+  // to a complete Value representation of the serialized form.  If the
+  // return value is true, the caller takes ownership of the objects pointed
+  // to by root.  If the return value is false, root should be unchanged.
+  virtual bool Deserialize(Value** root) = 0;
+};
+
+#endif  // CHROME_COMMON_VALUES_H__