qresource.cpp

奇趣公司比较新的qt/emd版本

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#include "qresource.h"
#include "qresource_p.h"
#include "qresource_iterator_p.h"
#include "qset.h"
#include "qhash.h"
#include "qmutex.h"
#include "qdebug.h"
#include "qlocale.h"
#include "qglobal.h"
#include "qvector.h"
#include "qdatetime.h"
#include "qbytearray.h"
#include "qstringlist.h"
#include <qshareddata.h>
#include <qplatformdefs.h>
#include "private/qabstractfileengine_p.h"

//#define DEBUG_RESOURCE_MATCH

//resource glue
class QResourceRoot
{
    enum Flags
    {
        Compressed = 0x01,
        Directory = 0x02
    };
    const uchar *tree, *names, *payloads;
    inline int findOffset(int node) const { return node * 14; } //sizeof each tree element
    int hash(int node) const;
    QString name(int node) const;
    short flags(int node) const;
public:
    mutable QAtomic ref;

    inline QResourceRoot(): tree(0), names(0), payloads(0) {}
    inline QResourceRoot(const uchar *t, const uchar *n, const uchar *d) { setSource(t, n, d); }
    virtual ~QResourceRoot() { }
    int findNode(const QString &path, const QLocale &locale=QLocale()) const;
    inline bool isContainer(int node) const { return flags(node) & Directory; }
    inline bool isCompressed(int node) const { return flags(node) & Compressed; }
    const uchar *data(int node, qint64 *size) const;
    QStringList children(int node) const;
    virtual QString mappingRoot() const { return QString(); }
    bool mappingRootSubdir(const QString &path, QString *match=0) const;
    inline bool operator==(const QResourceRoot &other) const
    { return tree == other.tree && names == other.names && payloads == other.payloads; }
    inline bool operator!=(const QResourceRoot &other) const
    { return !operator==(other); }
    enum ResourceRootType { Resource_Builtin, Resource_File, Resource_Buffer };
    virtual ResourceRootType type() const { return Resource_Builtin; }

protected:
    inline void setSource(const uchar *t, const uchar *n, const uchar *d) {
        tree = t;
        names = n;
        payloads = d;
    }
};

Q_DECLARE_TYPEINFO(QResourceRoot, Q_MOVABLE_TYPE);

Q_GLOBAL_STATIC_WITH_ARGS(QMutex, resourceMutex, (QMutex::Recursive))

typedef QList<QResourceRoot*> ResourceList;
Q_GLOBAL_STATIC(ResourceList, resourceList)

Q_GLOBAL_STATIC(QStringList, resourceSearchPaths)

/*!
    \class QResource
    \brief The QResource class provides an interface for reading directly from resources.

    \ingroup io
    \mainclass
    \reentrant
    \since 4.2

    QResource is an object that represents a set of data (and possibly
    children) relating to a single resource entity. QResource gives direct
    access to the bytes in their raw format. In this way direct access
    allows reading data without buffer copying or indirection. Indirection
    is often useful when interacting with the resource entity as if it is a
    file, this can be achieved with QFile. The data and children behind a
    QResource are normally compiled into an application/library, but it is
    also possible to load a resource at runtime. When loaded at run time
    the resource file will be loaded as one big set of data and then given
    out in pieces via references into the resource tree.

    A QResource can either be loaded with an absolute path, either treated
    as a file system rooted with a \c{/} character, or in resource notation
    rooted with a \c{:} character. A relative resource can also be opened
    which will be found through the searchPaths().

    A QResource that is representing a file will have data backing it, this
    data can possibly be compressed, in which case qUncompress() must be
    used to access the real data; this happens implicitly when accessed
    through a QFile. A QResource that is representing a directory will have
    only children and no data.

    \section1 Dynamic Resource Loading

    A resource can be left out of an application's binary and loaded when
    it is needed at run-time by using the registerResource() function. The
    resource file passed into registerResource() must be a binary resource
    as created by rcc. Further information about binary resources can be
    found in \l{The Qt Resource System} documentation.

    This can often be useful when loading a large set of application icons
    that may change based on a setting, or that can be edited by a user and
    later recreated. The resource is immediately loaded into memory, either
    as a result of a single file read operation, or as a memory mapped file.

    This approach can prove to be a significant performance gain as only a
    single file will be loaded, and pieces of data will be given out via the
    path requested in setFileName().

    The unregisterResource() function removes a reference to a particular
    file. If there are QResources that currently reference resources related
    to the unregistered file, they will continue to be valid but the resource
    file itself will be removed from the resource roots, and thus no further
    QResource can be created pointing into this resource data. The resource
    itself will be unmapped from memory when the last QResource points into it.

    \sa {The Qt Resource System}, QFile, QDir, QFileInfo
*/

class QResourcePrivate {
public:
    inline QResourcePrivate(QResource *_q) : q_ptr(_q) { clear(); }
    inline ~QResourcePrivate() { clear(); }

    void ensureInitialized() const;
    void ensureChildren() const;

    bool load(const QString &file);
    void clear();

    QLocale locale;
    QString fileName, absoluteFilePath;
    QList<QResourceRoot*> related;
    uint container : 1;
    mutable uint compressed : 1;
    mutable qint64 size;
    mutable const uchar *data;
    mutable QStringList children;

    QResource *q_ptr;
    Q_DECLARE_PUBLIC(QResource)
};

void
QResourcePrivate::clear()
{
    absoluteFilePath.clear();
    compressed = 0;
    data = 0;
    size = 0;
    children.clear();
    container = 0;
    for(int i = 0; i < related.size(); ++i) {
        QResourceRoot *root = related.at(i);
        if(!root->ref.deref())
            delete root;
    }
    related.clear();
}

bool
QResourcePrivate::load(const QString &file)
{
    related.clear();
    QMutexLocker lock(resourceMutex());
    const ResourceList *list = resourceList();
    for(int i = 0; i < list->size(); ++i) {
        QResourceRoot *res = list->at(i);
        const int node = res->findNode(file);
        if(node != -1) {
            if(related.isEmpty()) {
                container = res->isContainer(node);
                if(!container) {
                    data = res->data(node, &size);
                    compressed = res->isCompressed(node);
                } else {
                    data = 0;
                    size = 0;
                    compressed = 0;
                }
            } else if(res->isContainer(node) != container) {
                qWarning("QResourceInfo: Resource [%s] has both data and children!", file.toLatin1().constData());
            }
            res->ref.ref();
            related.append(res);
        } else if(res->mappingRootSubdir(file)) {
            container = true;
            data = 0;
            size = 0;
            compressed = 0;
            res->ref.ref();
            related.append(res);
        }
    }
    return !related.isEmpty();
}

void
QResourcePrivate::ensureInitialized() const
{
    if(!related.isEmpty())
        return;
    QResourcePrivate *that = const_cast<QResourcePrivate *>(this);
    if(fileName == QLatin1String(":"))
        that->fileName += QLatin1Char('/');
    that->absoluteFilePath = fileName;
    if(!that->absoluteFilePath.startsWith(QLatin1Char(':')))
        that->absoluteFilePath.prepend(QLatin1Char(':'));

    QString path = fileName;
    if(path.startsWith(QLatin1Char(':')))
        path = path.mid(1);

    bool found = false;
    if(path.startsWith(QLatin1Char('/'))) {
        found = that->load(path);
    } else {
        QMutexLocker lock(resourceMutex());
        QStringList searchPaths = *resourceSearchPaths();
        searchPaths << QLatin1String("");
        for(int i = 0; i < searchPaths.size(); ++i) {
            const QString searchPath(searchPaths.at(i) + QLatin1Char('/') + path);
            if(that->load(searchPath)) {
                found = true;
                that->absoluteFilePath = QLatin1Char(':') + searchPath;
                break;
            }
        }
    }
}

void
QResourcePrivate::ensureChildren() const
{
    ensureInitialized();
    if(!children.isEmpty() || !container || related.isEmpty())
        return;

    QString path = absoluteFilePath, k;
    if(path.startsWith(QLatin1Char(':')))
        path = path.mid(1);
    QSet<QString> kids;
    for(int i = 0; i < related.size(); ++i) {
        QResourceRoot *res = related.at(i);
        if(res->mappingRootSubdir(path, &k) && !k.isEmpty()) {
            if(!kids.contains(k)) {
                children += k;
                kids.insert(k);
            }
        } else {
            const int node = res->findNode(path);
            if(node != -1) {
                QStringList related_children = res->children(node);
                for(int kid = 0; kid < related_children.size(); ++kid) {
                    k = related_children.at(kid);
                    if(!kids.contains(k)) {
                        children += k;
                        kids.insert(k);
                    }
                }
            }
        }
    }
}

/*!
    Constructs a QResource pointing to \a file. \a locale is used to
    load a specific localization of a resource data.

    \sa QFileInfo, searchPaths(), setFileName(), setLocale()
*/

QResource::QResource(const QString &file, const QLocale &locale) : d_ptr(new QResourcePrivate(this))
{
    Q_D(QResource);
    d->fileName = file;
    d->locale = locale;
}

/*!
    Releases the resources of the QResource object.
*/
QResource::~QResource()
{
    delete d_ptr;
}

/*!
    Sets a QResource to only load the localization of resource to for \a
    locale. If a resource for the specific locale is not found then the
    C locale is used.

    \sa setFileName()
*/

void QResource::setLocale(const QLocale &locale)
{
    Q_D(QResource);
    d->clear();
    d->locale = locale;
}

/*!
    Returns the locale used to locate the data for the QResource.
*/

QLocale QResource::locale() const
{
    Q_D(const QResource);
    return d->locale;
}

/*!
    Sets a QResource to point to \a file. \a file can either be absolute,
    in which case it is opened directly, if relative then the file will be
    tried to be found in searchPaths().

    \sa absoluteFilePath()
*/

void QResource::setFileName(const QString &file)
{
    Q_D(QResource);
    d->clear();
    d->fileName = file;
}

/*!
    Returns the full path to the file that this QResource represents as it
    was passed.

    \sa absoluteFilePath()
*/

QString QResource::fileName() const
{
    Q_D(const QResource);
    d->ensureInitialized();
    return d->fileName;
}

/*!
    Returns the real path that this QResource represents, if the resource
    was found via the searchPaths() it will be indicated in the path.

    \sa fileName()
*/

QString QResource::absoluteFilePath() const
{
    Q_D(const QResource);
    d->ensureInitialized();
    return d->absoluteFilePath;
}

/*!
    Returns true if the resource really exists in the resource heirarchy,
    false otherwise.

*/

bool QResource::isValid() const
{
    Q_D(const QResource);
    d->ensureInitialized();
    return !d->related.isEmpty();
}

/*!
    \fn bool QResource::isFile() const

    Returns true if the resource represents a file and thus has data
    backing it, false if it represents a directory.

    \sa isDir()
*/


/*!
    Returns true if the resource represents a file and the data backing it
    is in a compressed format, false otherwise.

    \sa data(), isFile()
*/

bool QResource::isCompressed() const
{
    Q_D(const QResource);
    d->ensureInitialized();
    return d->compressed;
}

/*!
    Returns the size of the data backing the resource.

    \sa data(), isFile()
*/

qint64 QResource::size() const
{
    Q_D(const QResource);
    d->ensureInitialized();
    return d->size;
}

/*!
    Returns direct access to a read only segment of data that this resource
    represents. If the resource is compressed the data returns is
    compressed and qUncompress() must be used to access the data. If the
    resource is a directory 0 is returned.

    \sa size(), isCompressed(), isFile()
*/

const uchar *QResource::data() const
{
    Q_D(const QResource);
    d->ensureInitialized();
    return d->data;
}

/*!
    Returns true if the resource represents a directory and thus may have
    children() in it, false if it represents a file.

    \sa isFile()
*/