qgpluginmanager.cpp

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.10平台上编译为嵌入式图形界面操作系统。

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#include "qgpluginmanager_p.h"
#ifndef QT_NO_COMPONENT
#include "qcomlibrary_p.h"
#include "qmap.h"
#include "qdir.h"

/*
  The following co-occurrence code is borrowed from Qt Linguist.

  How similar are two texts? The approach used here relies on
  co-occurrence matrices and is very efficient.

  Let's see with an example: how similar are "here" and "hither"?  The
  co-occurrence matrix M for "here" is M[h,e] = 1, M[e,r] = 1,
  M[r,e] = 1 and 0 elsewhere; the matrix N for "hither" is N[h,i] = 1,
  N[i,t] = 1, ..., N[h,e] = 1, N[e,r] = 1 and 0 elsewhere.  The union
  U of both matrices is the matrix U[i,j] = max { M[i,j], N[i,j] },
  and the intersection V is V[i,j] = min { M[i,j], N[i,j] }. The score
  for a pair of texts is

      score = (sum of V[i,j] over all i, j) / (sum of U[i,j] over all i, j),

  a formula suggested by Arnt Gulbrandsen. Here we have

      score = 2 / 6,

  or one third.

  The implementation differs from this in a few details.  Most
  importantly, repetitions are ignored; for input "xxx", M[x,x] equals
  1, not 2.
*/

/*
  Every character is assigned to one of 20 buckets so that the
  co-occurrence matrix requires only 20 * 20 = 400 bits, not
  256 * 256 = 65536 bits or even more if we want the whole Unicode.
  Which character falls in which bucket is arbitrary.

  The second half of the table is a replica of the first half, because of
  laziness.
*/
static const char indexOf[256] = {
    0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
    0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
//      !   "   #   $   %   &   '   (   )   *   +   ,   -   .   /
    0,  2,  6,  7,  10, 12, 15, 19, 2,  6,  7,  10, 12, 15, 19, 0,
//  0   1   2   3   4   5   6   7   8   9   :   ;   <   =   >   ?
    1,  3,  4,  5,  8,  9,  11, 13, 14, 16, 2,  6,  7,  10, 12, 15,
//  @   A   B   C   D   E   F   G   H   I   J   K   L   M   N   O
    0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  6,  10, 11, 12, 13, 14,
//  P   Q   R   S   T   U   V   W   X   Y   Z   [   \   ]   ^   _
    15, 12, 16, 17, 18, 19, 2,  10, 15, 7,  19, 2,  6,  7,  10, 0,
//  `   a   b   c   d   e   f   g   h   i   j   k   l   m   n   o
    0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  6,  10, 11, 12, 13, 14,
//  p   q   r   s   t   u   v   w   x   y   z   {   |   }   ~
    15, 12, 16, 17, 18, 19, 2,  10, 15, 7,  19, 2,  6,  7,  10, 0,

    0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
    0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
    0,  2,  6,  7,  10, 12, 15, 19, 2,  6,  7,  10, 12, 15, 19, 0,
    1,  3,  4,  5,  8,  9,  11, 13, 14, 16, 2,  6,  7,  10, 12, 15,
    0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  6,  10, 11, 12, 13, 14,
    15, 12, 16, 17, 18, 19, 2,  10, 15, 7,  19, 2,  6,  7,  10, 0,
    0,  1,  2,  3,  4,  5,  6,  7,  8,  9,  6,  10, 11, 12, 13, 14,
    15, 12, 16, 17, 18, 19, 2,  10, 15, 7,  19, 2,  6,  7,  10, 0
};

/*
  The entry bitCount[i] (for i between 0 and 255) is the number of
  bits used to represent i in binary.
*/
static const char bitCount[256] = {
    0,  1,  1,  2,  1,  2,  2,  3,  1,  2,  2,  3,  2,  3,  3,  4,
    1,  2,  2,  3,  2,  3,  3,  4,  2,  3,  3,  4,  3,  4,  4,  5,
    1,  2,  2,  3,  2,  3,  3,  4,  2,  3,  3,  4,  3,  4,  4,  5,
    2,  3,  3,  4,  3,  4,  4,  5,  3,  4,  4,  5,  4,  5,  5,  6,
    1,  2,  2,  3,  2,  3,  3,  4,  2,  3,  3,  4,  3,  4,  4,  5,
    2,  3,  3,  4,  3,  4,  4,  5,  3,  4,  4,  5,  4,  5,  5,  6,
    2,  3,  3,  4,  3,  4,  4,  5,  3,  4,  4,  5,  4,  5,  5,  6,
    3,  4,  4,  5,  4,  5,  5,  6,  4,  5,  5,  6,  5,  6,  6,  7,
    1,  2,  2,  3,  2,  3,  3,  4,  2,  3,  3,  4,  3,  4,  4,  5,
    2,  3,  3,  4,  3,  4,  4,  5,  3,  4,  4,  5,  4,  5,  5,  6,
    2,  3,  3,  4,  3,  4,  4,  5,  3,  4,  4,  5,  4,  5,  5,  6,
    3,  4,  4,  5,  4,  5,  5,  6,  4,  5,  5,  6,  5,  6,  6,  7,
    2,  3,  3,  4,  3,  4,  4,  5,  3,  4,  4,  5,  4,  5,  5,  6,
    3,  4,  4,  5,  4,  5,  5,  6,  4,  5,  5,  6,  5,  6,  6,  7,
    3,  4,  4,  5,  4,  5,  5,  6,  4,  5,  5,  6,  5,  6,  6,  7,
    4,  5,  5,  6,  5,  6,  6,  7,  5,  6,  6,  7,  6,  7,  7,  8
};

class QCoMatrix
{
public:
    /*
      The matrix has 20 * 20 = 400 entries. This requires 50 bytes, or
      13 words. Some operations are performed on words for more
      efficiency.
    */
    union {
	Q_UINT8 b[52];
	Q_UINT32 w[13];
    };

    QCoMatrix() { memset( b, 0, 52 ); }
    QCoMatrix( const char *text ) {
	char c = '\0', d;
	memset( b, 0, 52 );
	while ( (d = *text) != '\0' ) {
	    setCoocc( c, d );
	    if ( (c = *++text) != '\0' ) {
		setCoocc( d, c );
		text++;
	    }
	}
    }

    void setCoocc( char c, char d ) {
	int k = indexOf[(uchar) c] + 20 * indexOf[(uchar) d];
	b[k >> 3] |= k & 0x7;
    }

    int worth() const {
	int result = 0;
	for ( int i = 0; i < 50; i++ )
	    result += bitCount[b[i]];
	return result;
    }

    static QCoMatrix reunion( const QCoMatrix& m, const QCoMatrix& n )
    {
	QCoMatrix p;
	for ( int i = 0; i < 13; i++ )
	    p.w[i] = m.w[i] | n.w[i];
	return p;
    }
    static QCoMatrix intersection( const QCoMatrix& m, const QCoMatrix& n )
    {
	QCoMatrix p;
	for ( int i = 0; i < 13; i++ )
	    p.w[i] = m.w[i] & n.w[i];
	return p;
    }
};

/*
  Returns an integer between 0 (dissimilar) and 15 (very similar)
  depending on  how similar the string is to \a target.

  This function is efficient, but its results might change in future
  versions of Qt as the algorithm evolves.

  \code
    QString s( "color" );
    a = similarity( s, "color" );  // a == 15
    a = similarity( s, "colour" ); // a == 8
    a = similarity( s, "flavor" ); // a == 4
    a = similarity( s, "dahlia" ); // a == 0
  \endcode
*/
static int similarity( const QString& s1, const QString& s2 )
{
    QCoMatrix m1( s1 );
    QCoMatrix m2( s2 );
    return ( 15 * (QCoMatrix::intersection(m1, m2).worth() + 1) ) /
	   ( QCoMatrix::reunion(m1, m2).worth() + 1 );
}

/*!
  \class QPluginManager qpluginmanager.h
  \reentrant
  \brief The QPluginManager class provides basic functions to access a certain kind of functionality in libraries.
  \ingroup componentmodel

  \internal

  A common usage of components is to extend the existing functionality in an application using plugins. The application
  defines interfaces that abstract a certain group of functionality, and a plugin provides a specialized implementation
  of one or more of those interfaces.

  The QPluginManager template has to be instantiated with an interface definition and the IID for this interface.

  \code
  QPluginManager<MyPluginInterface> *manager = new QPluginManager<MyPluginInterface>( IID_MyPluginInterface );
  \endcode

  It searches a specified directory for all shared libraries, queries for components that implement the specific interface and
  reads information about the features the plugin wants to add to the application. The component can provide the set of features
  provided by implementing either the QFeatureListInterface or the QComponentInformationInterface. The strings returned by the implementations
  of

  \code
  QStringList QFeatureListInterface::featureList() const
  \endcode

  or

  \code
  QString QComponentInformationInterface::name() const
  \endcode

  respectively, can then be used to access the component that provides the requested feature:

  \code
  MyPluginInterface *iface;
  manager->queryInterface( "feature", &iface );
  if ( iface )
      iface->execute( "feature" );
  \endcode

  The application can use a QPluginManager instance to create parts of the user interface based on the list of features
  found in plugins:

  \code
  QPluginManager<MyPluginInterface> *manager = new QPluginManager<MyPluginInterface>( IID_ImageFilterInterface );
  manager->addLibraryPath(...);

  QStringList features = manager->featureList();
  for ( QStringList::Iterator it = features.begin(); it != features.end(); ++it ) {
      MyPluginInterface *iface;
      manager->queryInterface( *it, &iface );

      // use QAction to provide toolbuttons and menuitems for each feature...
  }
  \endcode
*/

/*!
  \fn QPluginManager::QPluginManager( const QUuid& id, const QStringList& paths = QString::null, const QString &suffix = QString::null, bool cs = TRUE )

  Creates an QPluginManager for interfaces \a id that will load all shared library files in the \a paths + \a suffix.
  If \a cs is FALSE the manager will handle feature strings case insensitive.

  \warning
  Setting the cs flag to FALSE requires that components also convert to lower case when comparing with passed strings, so this has
  to be handled with care and documented very well.

  \sa QApplication::libraryPaths()
*/