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Introduced preliminary support for asynchronous file read requests,

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ReaderWriter::ReadResult now has a FILE_REQUEST enum.
  ReaderWriter::Options now has a s/getAsynchronousFileReadHint() parameter methods.

  libcurl based plugin now detects enabing of the AsynchronousFileReadHint, but
  as yet does not handle async requests - handling everything syncronously.
  
  DatabasePager now by default will enable AsynchronousFileReadHint for http
  based file requests
This commit is contained in:
Robert Osfield
2008-05-14 17:03:57 +00:00
parent d7c4e6f26e
commit 646fc43747
3 changed files with 53 additions and 9 deletions
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39
include/osgDB/ReaderWriter
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@@ -90,17 +90,21 @@ class OSGDB_EXPORT ReaderWriter : public osg::Object
Options():
osg::Object(true),
_objectCacheHint(CACHE_ARCHIVES) {}
_objectCacheHint(CACHE_ARCHIVES),
_asynchronousFileReadHint(false) {}
Options(const std::string& str):
osg::Object(true),
_str(str),
_objectCacheHint(CACHE_ARCHIVES) {}
_objectCacheHint(CACHE_ARCHIVES),
_asynchronousFileReadHint(false) {}
Options(const Options& options,const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY):
osg::Object(options,copyop),
_str(options._str),
_databasePaths(options._databasePaths),
_objectCacheHint(options._objectCacheHint) {}
_objectCacheHint(options._objectCacheHint),
_asynchronousFileReadHint(options._asynchronousFileReadHint) {}
META_Object(osgDB,Options);
@@ -119,12 +123,29 @@ class OSGDB_EXPORT ReaderWriter : public osg::Object
/** Get the const database path which is used a hint of where to look when loading models.*/
const FilePathList& getDatabasePathList() const { return _databasePaths; }
/** Set whether the Registry::ObjectCache should be used by default.*/
void setObjectCacheHint(CacheHintOptions useObjectCache) { _objectCacheHint = useObjectCache; }
/** Get whether the Registry::ObjectCache should be used by default.*/
CacheHintOptions getObjectCacheHint() const { return _objectCacheHint; }
/** Set Asynchrnous file read hint.
* This hint is used by plugins like the libcurl http reader plugin to inform them that
* they should make an internal file read requests to their background threads to load files,
* with the plugin returning immediately with a ReadResult::FILE_REQUESTED status. It is
* assumed that calls will continue to be made to the plugin until the background threads
* have read or failed to read the request file, at which point the return status which change
* to FILE_LOADED and the objects will be returned.
* Note, this facility is particular useful when using DatabasePager in conjunction with
* internet based databases where file load latency is relatively high.*/
void setAsynchronousFileReadHint(bool flag) { _asynchronousFileReadHint = flag; }
/** Get Asynchrnous file read hint. */
bool getAsynchronousFileReadHint() const { return _asynchronousFileReadHint; }
/** Sets a plugindata value PluginData with a string */
void setPluginData(const std::string& s, void* v) const { _pluginData[s] = v; }
@@ -148,6 +169,7 @@ class OSGDB_EXPORT ReaderWriter : public osg::Object
std::string _str;
FilePathList _databasePaths;
CacheHintOptions _objectCacheHint;
bool _asynchronousFileReadHint;
typedef std::map<std::string,void*> PluginDataMap;
mutable PluginDataMap _pluginData;
@@ -160,11 +182,12 @@ class OSGDB_EXPORT ReaderWriter : public osg::Object
enum ReadStatus
{
FILE_NOT_HANDLED, //!< file is not appropriate for this file reader, due to some incompatibility, but *not* a read error
FILE_NOT_FOUND, //!< file could not be found or could not be read
FILE_LOADED, //!< file successfully found, loaded, and converted into osg
FILE_LOADED_FROM_CACHE, //!< file found in cache and returned
ERROR_IN_READING_FILE //!< file found, loaded, but an error was encountered during processing
FILE_NOT_HANDLED, //!< File is not appropriate for this file reader, due to some incompatibility, but *not* a read error.
FILE_NOT_FOUND, //!< File could not be found or could not be read.
FILE_LOADED, //!< File successfully found, loaded, and converted into osg.
FILE_LOADED_FROM_CACHE, //!< File found in cache and returned.
ERROR_IN_READING_FILE, //!< File found, loaded, but an error was encountered during processing.
FILE_REQUESTED, //!< Asyncronous file read has been requested, but returning immediatiely, keep polling plugin till file read has been completed.
};
ReadResult(ReadStatus status=FILE_NOT_HANDLED):_status(status) {}

18
src/osgDB/DatabasePager.cpp
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@@ -1,5 +1,6 @@
#include <osgDB/DatabasePager>
#include <osgDB/ReadFile>
#include <osgDB/FileNameUtils>
#include <osg/Geode>
#include <osg/Timer>
@@ -419,7 +420,22 @@ void DatabasePager::requestNodeFile(const std::string& fileName,osg::Group* grou
databaseRequest->_timestampLastRequest = timestamp;
databaseRequest->_priorityLastRequest = priority;
databaseRequest->_groupForAddingLoadedSubgraph = group;
databaseRequest->_loadOptions = loadOptions;
if ((Registry::instance()->getOptions()==loadOptions) &&
(loadOptions ? !loadOptions->getAsynchronousFileReadHint() : true) &&
osgDB::containsServerAddress(fileName))
{
// we need to enable asynchronous file reading.
databaseRequest->_loadOptions = loadOptions ?
dynamic_cast<osgDB::ReaderWriter::Options*>(loadOptions->clone(osg::CopyOp::SHALLOW_COPY)) :
new osgDB::ReaderWriter::Options;
databaseRequest->_loadOptions->setAsynchronousFileReadHint(true);
}
else
{
databaseRequest->_loadOptions = loadOptions;
}
_fileRequestList.push_back(databaseRequest);

5
src/osgPlugins/curl/ReaderWriterCURL.cpp
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@@ -316,6 +316,11 @@ class ReaderWriterCURL : public osgDB::ReaderWriter
proxyAddress = std::string(proxyEnvAddress) + ":8080"; //Default
}
bool asyncFileRead = options ? options->getAsynchronousFileReadHint() : false;
osg::notify(osg::INFO)<<"AsynchronousFileReadHint= "<<asyncFileRead<<std::endl;
// if (asyncFileRead) return ReadResult::FILE_REQUESTED;
std::stringstream buffer;
ReadResult curlResult;