File qthelper.hpp of Package subtitlecomposer
/* Copyright (C) 2017 the mpv developers
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef MPV_CLIENT_API_QTHELPER_H_
#define MPV_CLIENT_API_QTHELPER_H_
#include <mpv/client.h>
#if !MPV_ENABLE_DEPRECATED
#error "This helper is deprecated. Copy it into your project instead."
#else
/**
* Note: these helpers are provided for convenience for C++/Qt applications.
* This is based on the public API in client.h, and it does not encode any
* knowledge that is not known or guaranteed outside of the C client API. You
* can even copy and modify this code as you like, or implement similar things
* for other languages.
*/
#include <cstring>
#include <QVariant>
#include <QString>
#include <QList>
#include <QHash>
#include <QSharedPointer>
#include <QMetaType>
namespace mpv {
namespace qt {
// Wrapper around mpv_handle. Does refcounting under the hood.
class Handle
{
struct container {
container(mpv_handle *h) : mpv(h) {}
~container() { mpv_terminate_destroy(mpv); }
mpv_handle *mpv;
};
QSharedPointer<container> sptr;
public:
// Construct a new Handle from a raw mpv_handle with refcount 1. If the
// last Handle goes out of scope, the mpv_handle will be destroyed with
// mpv_terminate_destroy().
// Never destroy the mpv_handle manually when using this wrapper. You
// will create dangling pointers. Just let the wrapper take care of
// destroying the mpv_handle.
// Never create multiple wrappers from the same raw mpv_handle; copy the
// wrapper instead (that's what it's for).
static Handle FromRawHandle(mpv_handle *handle) {
Handle h;
h.sptr = QSharedPointer<container>(new container(handle));
return h;
}
// Return the raw handle; for use with the libmpv C API.
operator mpv_handle*() const { return sptr ? (*sptr).mpv : 0; }
};
static inline QVariant node_to_variant(const mpv_node *node)
{
switch (node->format) {
case MPV_FORMAT_STRING:
return QVariant(QString::fromUtf8(node->u.string));
case MPV_FORMAT_FLAG:
return QVariant(static_cast<bool>(node->u.flag));
case MPV_FORMAT_INT64:
return QVariant(static_cast<qlonglong>(node->u.int64));
case MPV_FORMAT_DOUBLE:
return QVariant(node->u.double_);
case MPV_FORMAT_NODE_ARRAY: {
mpv_node_list *list = node->u.list;
QVariantList qlist;
for (int n = 0; n < list->num; n++)
qlist.append(node_to_variant(&list->values[n]));
return QVariant(qlist);
}
case MPV_FORMAT_NODE_MAP: {
mpv_node_list *list = node->u.list;
QVariantMap qmap;
for (int n = 0; n < list->num; n++) {
qmap.insert(QString::fromUtf8(list->keys[n]),
node_to_variant(&list->values[n]));
}
return QVariant(qmap);
}
default: // MPV_FORMAT_NONE, unknown values (e.g. future extensions)
return QVariant();
}
}
struct node_builder {
node_builder(const QVariant& v) {
set(&node_, v);
}
~node_builder() {
free_node(&node_);
}
mpv_node *node() { return &node_; }
private:
Q_DISABLE_COPY(node_builder)
mpv_node node_;
mpv_node_list *create_list(mpv_node *dst, bool is_map, int num) {
dst->format = is_map ? MPV_FORMAT_NODE_MAP : MPV_FORMAT_NODE_ARRAY;
mpv_node_list *list = new mpv_node_list();
dst->u.list = list;
if (!list)
goto err;
list->values = new mpv_node[num]();
if (!list->values)
goto err;
if (is_map) {
list->keys = new char*[num]();
if (!list->keys)
goto err;
}
return list;
err:
free_node(dst);
return NULL;
}
char *dup_qstring(const QString &s) {
QByteArray b = s.toUtf8();
char *r = new char[b.size() + 1];
if (r)
std::memcpy(r, b.data(), b.size() + 1);
return r;
}
bool test_type(const QVariant &v, QMetaType::Type t) {
// The Qt docs say: "Although this function is declared as returning
// "QVariant::Type(obsolete), the return value should be interpreted
// as QMetaType::Type."
// So a cast really seems to be needed to avoid warnings (urgh).
return static_cast<int>(v.type()) == static_cast<int>(t);
}
void set(mpv_node *dst, const QVariant &src) {
if (test_type(src, QMetaType::QString)) {
dst->format = MPV_FORMAT_STRING;
dst->u.string = dup_qstring(src.toString());
if (!dst->u.string)
goto fail;
} else if (test_type(src, QMetaType::Bool)) {
dst->format = MPV_FORMAT_FLAG;
dst->u.flag = src.toBool() ? 1 : 0;
} else if (test_type(src, QMetaType::Int) ||
test_type(src, QMetaType::LongLong) ||
test_type(src, QMetaType::UInt) ||
test_type(src, QMetaType::ULongLong))
{
dst->format = MPV_FORMAT_INT64;
dst->u.int64 = src.toLongLong();
} else if (test_type(src, QMetaType::Double)) {
dst->format = MPV_FORMAT_DOUBLE;
dst->u.double_ = src.toDouble();
} else if (src.canConvert<QVariantList>()) {
QVariantList qlist = src.toList();
mpv_node_list *list = create_list(dst, false, qlist.size());
if (!list)
goto fail;
list->num = qlist.size();
for (int n = 0; n < qlist.size(); n++)
set(&list->values[n], qlist[n]);
} else if (src.canConvert<QVariantMap>()) {
QVariantMap qmap = src.toMap();
mpv_node_list *list = create_list(dst, true, qmap.size());
if (!list)
goto fail;
list->num = qmap.size();
for (int n = 0; n < qmap.size(); n++) {
list->keys[n] = dup_qstring(qmap.keys()[n]);
if (!list->keys[n]) {
free_node(dst);
goto fail;
}
set(&list->values[n], qmap.values()[n]);
}
} else {
goto fail;
}
return;
fail:
dst->format = MPV_FORMAT_NONE;
}
void free_node(mpv_node *dst) {
switch (dst->format) {
case MPV_FORMAT_STRING:
delete[] dst->u.string;
break;
case MPV_FORMAT_NODE_ARRAY:
case MPV_FORMAT_NODE_MAP: {
mpv_node_list *list = dst->u.list;
if (list) {
for (int n = 0; n < list->num; n++) {
if (list->keys)
delete[] list->keys[n];
if (list->values)
free_node(&list->values[n]);
}
delete[] list->keys;
delete[] list->values;
}
delete list;
break;
}
default: ;
}
dst->format = MPV_FORMAT_NONE;
}
};
/**
* RAII wrapper that calls mpv_free_node_contents() on the pointer.
*/
struct node_autofree {
mpv_node *ptr;
node_autofree(mpv_node *a_ptr) : ptr(a_ptr) {}
~node_autofree() { mpv_free_node_contents(ptr); }
};
#if MPV_ENABLE_DEPRECATED
/**
* Return the given property as mpv_node converted to QVariant, or QVariant()
* on error.
*
* @deprecated use get_property() instead
*
* @param name the property name
*/
static inline QVariant get_property_variant(mpv_handle *ctx, const QString &name)
{
mpv_node node;
if (mpv_get_property(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, &node) < 0)
return QVariant();
node_autofree f(&node);
return node_to_variant(&node);
}
/**
* Set the given property as mpv_node converted from the QVariant argument.
* @deprecated use set_property() instead
*/
static inline int set_property_variant(mpv_handle *ctx, const QString &name,
const QVariant &v)
{
node_builder node(v);
return mpv_set_property(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, node.node());
}
/**
* Set the given option as mpv_node converted from the QVariant argument.
*
* @deprecated use set_property() instead
*/
static inline int set_option_variant(mpv_handle *ctx, const QString &name,
const QVariant &v)
{
node_builder node(v);
return mpv_set_option(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, node.node());
}
/**
* mpv_command_node() equivalent. Returns QVariant() on error (and
* unfortunately, the same on success).
*
* @deprecated use command() instead
*/
static inline QVariant command_variant(mpv_handle *ctx, const QVariant &args)
{
node_builder node(args);
mpv_node res;
if (mpv_command_node(ctx, node.node(), &res) < 0)
return QVariant();
node_autofree f(&res);
return node_to_variant(&res);
}
#endif
/**
* This is used to return error codes wrapped in QVariant for functions which
* return QVariant.
*
* You can use get_error() or is_error() to extract the error status from a
* QVariant value.
*/
struct ErrorReturn
{
/**
* enum mpv_error value (or a value outside of it if ABI was extended)
*/
int error;
ErrorReturn() : error(0) {}
explicit ErrorReturn(int err) : error(err) {}
};
/**
* Return the mpv error code packed into a QVariant, or 0 (success) if it's not
* an error value.
*
* @return error code (<0) or success (>=0)
*/
static inline int get_error(const QVariant &v)
{
if (!v.canConvert<ErrorReturn>())
return 0;
return v.value<ErrorReturn>().error;
}
/**
* Return whether the QVariant carries a mpv error code.
*/
static inline bool is_error(const QVariant &v)
{
return get_error(v) < 0;
}
/**
* Return the given property as mpv_node converted to QVariant, or QVariant()
* on error.
*
* @param name the property name
* @return the property value, or an ErrorReturn with the error code
*/
static inline QVariant get_property(mpv_handle *ctx, const QString &name)
{
mpv_node node;
int err = mpv_get_property(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, &node);
if (err < 0)
return QVariant::fromValue(ErrorReturn(err));
node_autofree f(&node);
return node_to_variant(&node);
}
/**
* Set the given property as mpv_node converted from the QVariant argument.
*
* @return mpv error code (<0 on error, >= 0 on success)
*/
static inline int set_property(mpv_handle *ctx, const QString &name,
const QVariant &v)
{
node_builder node(v);
return mpv_set_property(ctx, name.toUtf8().data(), MPV_FORMAT_NODE, node.node());
}
/**
* mpv_command_node() equivalent.
*
* @param args command arguments, with args[0] being the command name as string
* @return the property value, or an ErrorReturn with the error code
*/
static inline QVariant command(mpv_handle *ctx, const QVariant &args)
{
node_builder node(args);
mpv_node res;
int err = mpv_command_node(ctx, node.node(), &res);
if (err < 0)
return QVariant::fromValue(ErrorReturn(err));
node_autofree f(&res);
return node_to_variant(&res);
}
}
}
Q_DECLARE_METATYPE(mpv::qt::ErrorReturn)
#endif /* else #if MPV_ENABLE_DEPRECATED */
#endif
