// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef PPAPI_CPP_VAR_H_
#define PPAPI_CPP_VAR_H_
#include <stdint.h>
#include <string>
#include "ppapi/c/pp_var.h"
#include "ppapi/cpp/pass_ref.h"
#include "ppapi/cpp/resource.h"
/// @file
/// This file defines the API for handling the passing of data types between
/// your module and the page.
namespace pp {
/// A generic type used for passing data types between the module and the page.
class Var {
public:
/// Special value passed to constructor to make <code>NULL</code>.
struct Null {};
/// Default constructor. Creates a <code>Var</code> of type
/// <code>Undefined</code>.
Var();
/// A constructor used to create a <code>Var</code> of type <code>Null</code>.
Var(Null);
/// A constructor used to create a <code>Var</code> of type <code>Bool</code>.
///
/// @param[in] b A boolean value.
Var(bool b);
/// A constructor used to create a 32 bit integer <code>Var</code>.
///
/// @param[in] i A 32 bit integer value.
Var(int32_t i);
/// A constructor used to create a double value <code>Var</code>.
///
/// @param[in] d A double value.
Var(double d);
/// A constructor used to create a UTF-8 character <code>Var</code>.
Var(const char* utf8_str); // Must be encoded in UTF-8.
/// A constructor used to create a UTF-8 character <code>Var</code>.
Var(const std::string& utf8_str); // Must be encoded in UTF-8.
/// A constructor used to create a resource <code>Var</code>.
explicit Var(const pp::Resource& resource);
/// A constructor used when you have received a <code>Var</code> as a return
/// value that has had its reference count incremented for you.
///
/// You will not normally need to use this constructor because
/// the reference count will not normally be incremented for you.
Var(PassRef, const PP_Var& var) {
var_ = var;
is_managed_ = true;
}
/// A constructor that increments the reference count.
explicit Var(const PP_Var& var);
struct DontManage {};
/// This constructor is used when we've given a <code>PP_Var</code> as an
/// input argument from somewhere and that reference is managing the
/// reference count for us. The object will not have its reference count
/// increased or decreased by this class instance.
///
/// @param[in] var A <code>Var</code>.
Var(DontManage, const PP_Var& var) {
var_ = var;
is_managed_ = false;
}
/// A constructor for copying a <code>Var</code>.
Var(const Var& other);
/// Destructor.
virtual ~Var();
/// This function assigns one <code>Var</code> to another <code>Var</code>.
///
/// @param[in] other The <code>Var</code> to be assigned.
///
/// @return A resulting <code>Var</code>.
virtual Var& operator=(const Var& other);
/// This function compares object identity (rather than value identity) for
/// objects, dictionaries, and arrays
///
/// @param[in] other The <code>Var</code> to be compared to this Var.
///
/// @return true if the <code>other</code> <code>Var</code> is the same as
/// this <code>Var</code>, otherwise false.
bool operator==(const Var& other) const;
/// This function determines if this <code>Var</code> is an undefined value.
///
/// @return true if this <code>Var</code> is undefined, otherwise false.
bool is_undefined() const { return var_.type == PP_VARTYPE_UNDEFINED; }
/// This function determines if this <code>Var</code> is a null value.
///
/// @return true if this <code>Var</code> is null, otherwise false.
bool is_null() const { return var_.type == PP_VARTYPE_NULL; }
/// This function determines if this <code>Var</code> is a bool value.
///
/// @return true if this <code>Var</code> is a bool, otherwise false.
bool is_bool() const { return var_.type == PP_VARTYPE_BOOL; }
/// This function determines if this <code>Var</code> is a string value.
///
/// @return true if this <code>Var</code> is a string, otherwise false.
bool is_string() const { return var_.type == PP_VARTYPE_STRING; }
/// This function determines if this <code>Var</code> is an object.
///
/// @return true if this <code>Var</code> is an object, otherwise false.
bool is_object() const { return var_.type == PP_VARTYPE_OBJECT; }
/// This function determines if this <code>Var</code> is an array.
///
/// @return true if this <code>Var</code> is an array, otherwise false.
bool is_array() const { return var_.type == PP_VARTYPE_ARRAY; }
/// This function determines if this <code>Var</code> is a dictionary.
///
/// @return true if this <code>Var</code> is a dictionary, otherwise false.
bool is_dictionary() const { return var_.type == PP_VARTYPE_DICTIONARY; }
/// This function determines if this <code>Var</code> is a resource.
///
/// @return true if this <code>Var</code> is a resource, otherwise false.
bool is_resource() const { return var_.type == PP_VARTYPE_RESOURCE; }
/// This function determines if this <code>Var</code> is an integer value.
/// The <code>is_int</code> function returns the internal representation.
/// The JavaScript runtime may convert between the two as needed, so the
/// distinction may not be relevant in all cases (int is really an
/// optimization inside the runtime). So most of the time, you will want
/// to check is_number().
///
/// @return true if this <code>Var</code> is an integer, otherwise false.
bool is_int() const { return var_.type == PP_VARTYPE_INT32; }
/// This function determines if this <code>Var</code> is a double value.
/// The <code>is_double</code> function returns the internal representation.
/// The JavaScript runtime may convert between the two as needed, so the
/// distinction may not be relevant in all cases (int is really an
/// optimization inside the runtime). So most of the time, you will want to
/// check is_number().
///
/// @return true if this <code>Var</code> is a double, otherwise false.
bool is_double() const { return var_.type == PP_VARTYPE_DOUBLE; }
/// This function determines if this <code>Var</code> is a number.
///
/// @return true if this <code>Var</code> is an int32_t or double number,
/// otherwise false.
bool is_number() const {
return var_.type == PP_VARTYPE_INT32 ||
var_.type == PP_VARTYPE_DOUBLE;
}
/// This function determines if this <code>Var</code> is an ArrayBuffer.
bool is_array_buffer() const { return var_.type == PP_VARTYPE_ARRAY_BUFFER; }
/// AsBool() converts this <code>Var</code> to a bool. Assumes the
/// internal representation is_bool(). If it's not, it will assert in debug
/// mode, and return false.
///
/// @return A bool version of this <code>Var</code>.
bool AsBool() const;
/// AsInt() converts this <code>Var</code> to an int32_t. This function
/// is required because JavaScript doesn't have a concept of ints and doubles,
/// only numbers. The distinction between the two is an optimization inside
/// the compiler. Since converting from a double to an int may be lossy, if
/// you care about the distinction, either always work in doubles, or check
/// !is_double() before calling AsInt().
///
/// These functions will assert in debug mode and return 0 if the internal
/// representation is not is_number().
///
/// @return An int32_t version of this <code>Var</code>.
int32_t AsInt() const;
/// AsDouble() converts this <code>Var</code> to a double. This function is
/// necessary because JavaScript doesn't have a concept of ints and doubles,
/// only numbers. The distinction between the two is an optimization inside
/// the compiler. Since converting from a double to an int may be lossy, if
/// you care about the distinction, either always work in doubles, or check
/// !is_double() before calling AsInt().
///
/// These functions will assert in debug mode and return 0 if the internal
/// representation is not is_number().
///
/// @return An double version of this <code>Var</code>.
double AsDouble() const;
/// AsString() converts this <code>Var</code> to a string. If this object is
/// not a string, it will assert in debug mode, and return an empty string.
///
/// @return A string version of this <code>Var</code>.
std::string AsString() const;
/// Gets the resource contained in the var. If this object is not a resource,
/// it will assert in debug mode, and return a null resource.
///
/// @return The <code>pp::Resource</code> that is contained in the var.
pp::Resource AsResource() const;
/// This function returns the internal <code>PP_Var</code>
/// managed by this <code>Var</code> object.
///
/// @return A const reference to a <code>PP_Var</code>.
const PP_Var& pp_var() const {
return var_;
}
/// Detach() detaches from the internal <code>PP_Var</code> of this
/// object, keeping the reference count the same. This is used when returning
/// a <code>PP_Var</code> from an API function where the caller expects the
/// return value to have the reference count incremented for it.
///
/// @return A detached version of this object without affecting the reference
/// count.
PP_Var Detach() {
PP_Var ret = var_;
var_ = PP_MakeUndefined();
is_managed_ = true;
return ret;
}
/// DebugString() returns a short description "Var<X>" that can be used for
/// logging, where "X" is the underlying scalar or "UNDEFINED" or "OBJ" as
/// it does not call into the browser to get the object description.
///
/// @return A string displaying the value of this <code>Var</code>. This
/// function is used for debugging.
std::string DebugString() const;
/// This class is used when calling the raw C PPAPI when using the C++
/// <code>Var</code> as a possible NULL exception. This class will handle
/// getting the address of the internal value out if it's non-NULL and
/// fixing up the reference count.
///
/// <strong>Warning:</strong> this will only work for things with exception
/// semantics, i.e. that the value will not be changed if it's a
/// non-undefined exception. Otherwise, this class will mess up the
/// refcounting.
///
/// This is a bit subtle:
/// - If NULL is passed, we return NULL from get() and do nothing.
///
/// - If a undefined value is passed, we return the address of a undefined
/// var from get and have the output value take ownership of that var.
///
/// - If a non-undefined value is passed, we return the address of that var
/// from get, and nothing else should change.
///
/// Example:
/// void FooBar(a, b, Var* exception = NULL) {
/// foo_interface->Bar(a, b, Var::OutException(exception).get());
/// }
class OutException {
public:
/// A constructor.
OutException(Var* v)
: output_(v),
originally_had_exception_(v && !v->is_undefined()) {
if (output_) {
temp_ = output_->var_;
} else {
temp_.padding = 0;
temp_.type = PP_VARTYPE_UNDEFINED;
}
}
/// Destructor.
~OutException() {
if (output_ && !originally_had_exception_)
*output_ = Var(PASS_REF, temp_);
}
PP_Var* get() {
if (output_)
return &temp_;
return NULL;
}
private:
Var* output_;
bool originally_had_exception_;
PP_Var temp_;
};
protected:
PP_Var var_;
// |is_managed_| indicates if the instance manages |var_|.
// You need to check if |var_| is refcounted to call Release().
bool is_managed_;
private:
// Prevent an arbitrary pointer argument from being implicitly converted to
// a bool at Var construction. If somebody makes such a mistake, they will
// get a compilation error.
Var(void* non_scriptable_object_pointer);
};
} // namespace pp
#endif // PPAPI_CPP_VAR_H_
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