std::string getValue( XmlTransaction &txn, XmlManager &mgr, const XmlDocument &document,
const std::string &XPath, XmlQueryContext &context )
{
/////////////////////////////////////////////////////////////////////////////////
/////////// Return specific information from a document. /////////////////////
/////////// !!!!!! Assumes a result set of size 1 !!!!!!! /////////////////////
/////////////////////////////////////////////////////////////////////////////////
// Exception handling omitted....
//Perform the query
XmlQueryExpression doc_expr = mgr.prepare(txn, XPath, context);
XmlResults result = doc_expr.execute( txn, XmlValue(document), context);
//We require a result set size of 1.
assert( result.size() == 1 );
//Get the value. If we allowed the result set to be larger than size 1,
//we would have to loop through the results, processing each as is
//required by our application.
XmlValue value;
result.next(value);
return value.asString();
}
void ContextItemQueryCommand::execute(Args &args, Environment &env)
{
if(args.size() != 2) {
throw CommandException("Wrong number of arguments");
}
env.testResults();
XmlResults newResults = env.db().createResults();
env.results()->reset();
u_int32_t flags = DBXML_LAZY_DOCS;
if(env.documentProjection())
flags |= DBXML_DOCUMENT_PROJECTION;
if(env.txn()) {
XmlQueryExpression expr = env.db().prepare(*env.txn(), args[1], env.context());
XmlValue value;
while(env.results()->next(value)) {
XmlResults tmpResults = expr.execute(*env.txn(), value, env.context(), flags);
XmlValue tmpValue;
while(tmpResults.next(tmpValue)) {
newResults.add(tmpValue);
}
}
} else {
XmlQueryExpression expr = env.db().prepare(args[1], env.context());
XmlValue value;
while(env.results()->next(value)) {
XmlResults tmpResults = expr.execute(value, env.context(), flags);
XmlValue tmpValue;
while(tmpResults.next(tmpValue)) {
newResults.add(tmpValue);
}
}
}
env.deleteResults();
env.results() = new XmlResults(newResults);
if(env.verbose())
cout << (unsigned int)env.results()->size()
<< " objects returned for expression '"
<< args[1] << "'\n" << endl;
}
bool XmlQueryContext::getVariableValue(const string &name,
XmlValue &value) const
{
CHECK_POINTER;
XmlResults results;
bool success = queryContext_->getVariableValue(name, results);
if(!success) return false;
if(results.size() > 1) {
throw XmlException(XmlException::INVALID_VALUE,
"Variable has more than one value assigned to it");
}
results.reset();
results.next(value);
return true;
}
int
main(int argc, char **argv)
{
// This program uses a named container, which will apear
// on disk
std::string containerName = "people.dbxml";
std::string content = "<people><person><name>joe</name></person><person><name>mary</name></person></people>";
std::string docName = "people";
// Note that the query uses a variable, which must be set
// in the query context
std::string queryString =
"collection('people.dbxml')/people/person[name=$name]";
std::string environmentDir = ".";
// Berkeley DB environment flags
u_int32_t envFlags = DB_RECOVER|DB_CREATE|DB_INIT_MPOOL|
DB_INIT_LOCK|DB_INIT_TXN|DB_INIT_LOG;
// Berkeley DB cache size (25 MB). The default is quite small
u_int32_t envCacheSize = 25*1024*1024;
// argument parsing should really use getopt(), but
// avoid it for platform-independence
if (argc == 3) {
if (std::string(argv[1]) != std::string("-h"))
usage(argv[0]);
environmentDir = argv[2];
} else if (argc != 1)
usage(argv[0]);
// Create and open a Berkeley DB Transactional Environment.
int dberr;
DB_ENV *dbEnv = 0;
dberr = db_env_create(&dbEnv, 0);
if (dberr == 0) {
dbEnv->set_cachesize(dbEnv, 0, envCacheSize, 1);
dbEnv->set_errcall(dbEnv, errcall); // set error callback
dbEnv->set_lk_detect(dbEnv, DB_LOCK_DEFAULT); // handle deadlocks
dberr = dbEnv->open(dbEnv, environmentDir.c_str(), envFlags, 0);
}
if (dberr) {
std::cout << "Unable to create environment handle due to the following error: " <<
db_strerror(dberr) << std::endl;
if (dbEnv) dbEnv->close(dbEnv, 0);
return -1;
}
try {
// All BDB XML programs require an XmlManager instance.
// Create it from the DbEnv
XmlManager mgr(dbEnv, DBXML_ADOPT_DBENV);
// Because the container will exist on disk, remove it
// first if it exists
if (mgr.existsContainer(containerName))
mgr.removeContainer(containerName);
/* Create a container that is transactional. The container
* type is NodeContainer, which is the default container type,
* and the index is on nodes, which is the default for a
* NodeContainer container. XmlContainerConfig can be used
* to set the container type and index type.
*/
XmlContainerConfig config;
config.setTransactional(true);
XmlContainer cont = mgr.createContainer(
containerName,
config);
// All Container modification operations need XmlUpdateContext
XmlUpdateContext uc = mgr.createUpdateContext();
// The following putDocument call will auto-transact
// and will abort/cleanup if the operation deadlocks or
// otherwise fails
cont.putDocument(docName, content, uc);
// Querying requires an XmlQueryContext
XmlQueryContext qc = mgr.createQueryContext();
// Add a variable to the query context, used by the query
qc.setVariableValue("name", "mary");
// Use try/catch and while to handle deadlock/retry
int retry = 0;
while (retry < 5) { // hard-code 5 retries
// Create a new transaction for the query
XmlTransaction txn = mgr.createTransaction();
try {
// o Note the passing of txn to both methods
// o Often the XmlQueryExpression object will be created and
// saved for reuse in order to amortize the cost of parsing a query
XmlQueryExpression expr = mgr.prepare(txn, queryString, qc);
XmlResults res = expr.execute(txn, qc);
// Note use of XmlQueryExpression::getQuery() and
// XmlResults::size()
std::cout << "The query, '" << expr.getQuery() << "' returned " <<
(unsigned int)res.size() << " result(s)" << std::endl;
// Process results -- just print them
XmlValue value;
std::cout << "Result: " << std::endl;
while (res.next(value)) {
std::cout << "\t" << value.asString() << std::endl;
}
// done with the transaction
txn.commit();
break;
} catch (XmlException &x) {
txn.abort(); // unconditional
if ((x.getExceptionCode() == XmlException::DATABASE_ERROR) &&
(x.getDbErrno() == DB_LOCK_DEADLOCK)) {
++retry;
continue; // try again
}
throw; // re-throw -- not deadlock
}
}
// In C++, resources are released as objects go out
// of scope.
} catch (XmlException &xe) {
std::cout << "XmlException: " << xe.what() << std::endl;
}
return 0;
}
void MgResourceDefinitionManager::DeleteResource(
MgResourceIdentifier* resource, bool strict)
{
assert(NULL != resource);
MG_RESOURCE_SERVICE_TRY()
string resourcePathname;
MgUtil::WideCharToMultiByte(resource->ToString(), resourcePathname);
// Set up an XQuery.
string query;
if (resource->IsFolder())
{
query = "for $i in collection('";
query += m_container.getName();
query += "')";
query += "/*[starts-with(dbxml:metadata('dbxml:name'),'";
query += resourcePathname;
query += "')]";
query += " order by dbxml:metadata('dbxml:name', $i) descending return $i";
}
else
{
query = "collection('";
query += m_container.getName();
query += "')";
query += "/*[dbxml:metadata('dbxml:name')='";
query += resourcePathname;
query += "']";
}
// Execute the XQuery.
XmlManager& xmlManager = m_container.getManager();
XmlQueryContext queryContext = xmlManager.createQueryContext();
queryContext.setNamespace(MgResourceInfo::sm_metadataPrefix,
MgResourceInfo::sm_metadataUri);
XmlResults results = IsTransacted() ?
xmlManager.query(GetXmlTxn(), query, queryContext, 0) :
xmlManager.query(query, queryContext, 0);
if (0 == results.size())
{
if (!strict || (IsResourceContentManager() && resource->IsFolder()))
{
return;
}
else
{
m_repositoryMan.ThrowResourceNotFoundException(*resource,
L"MgResourceDefinitionManager.DeleteResource",
__LINE__, __WFILE__);
}
}
// Delete the resources.
MgResourceIdentifier currResource;
XmlUpdateContext updateContext = xmlManager.createUpdateContext();
XmlValue xmlValue;
while (results.next(xmlValue))
{
XmlDocument xmlDoc = xmlValue.asDocument();
currResource.SetResource(MgUtil::MultiByteToWideChar(xmlDoc.getName()));
if (!currResource.IsRoot())
{
DeleteDocument(currResource, xmlDoc, updateContext);
}
}
if (!resource->IsRoot())
{
m_repositoryMan.UpdateDateModifiedResourceSet(resource->GetFullPath(true));
}
MG_RESOURCE_CONTAINER_CATCH_AND_THROW(L"MgResourceDefinitionManager.DeleteResource")
}
/**
* @breif
* Get the number of nodes in a xml file
*
* @Param container_type
* should be value defined in container_index enum
* @Param doc
* the document name of xml file
* @Param node_path
* the xpath path of node to be search
*
* @Returns
* the node number
*/
int bdbXMLInterface::get_node_element_num (container_index container_type,
const string *doc,
const string *node_path)
{
string query_string;
int res = 0;
if (m_manager == NULL)
{
throw XmlException(XmlException::NULL_POINTER, "m_manager", __FILE__, __LINE__);
// return xml_exception;
}
if (container_type >= CONT_IDX_NUM)
{
throw XmlException(XmlException::INVALID_VALUE, "contianer_type", __FILE__, __LINE__);
// return para_error;
}
if (doc == NULL)
{
query_string += "count(collection('"
+ container_names[container_type]
+ ".dbxml')";
}
else
{
query_string += "count(doc(\"dbxml:/"
+ container_names[container_type]
+ ".dbxml/"
+ *doc
+ "\")";
}
if (node_path != NULL)
query_string += *node_path;
query_string += ")";
XmlQueryContext context = m_manager->createQueryContext();
XmlQueryExpression qe;
XmlResults results;
try
{
qe = m_manager->prepare(query_string, context);
results = qe.execute(context);
}
catch (XmlException &xe)
{
debugOut() << "get_node_element_num: " << query_string << endl;
debugOut() << "get_node_element_num exception: " << xe.what() << endl;
throw xe;
}
XmlValue value;
results.next(value);
if (value.isNumber())
res = (int)value.asNumber();
else
res = 0;
return res;
}
/**
* @breif
* get the node content of a document as a string
*
* @Param container_type
* should be value defined in container_index enum
* @Param doc
* the document name of xml file
* @Param node_path
* the xpath path of node to be search
* @Param res
* output parameter, return the string value of results
*
* @Returns
* return no_error for success
* otherwise an XmlException was throwed
*/
BdRetVal bdbXMLInterface::get_node(container_index container_type,
const string *doc,
const string *node_path,
string &res)
{
string query_string;
if (m_manager == NULL)
{
throw XmlException(XmlException::NULL_POINTER, "m_manager null", __FILE__, __LINE__);
}
if (container_type >= CONT_IDX_NUM)
{
throw XmlException(XmlException::INVALID_VALUE, "contianer_type", __FILE__, __LINE__);
}
if (doc == NULL)
{
query_string += "collection('"
+ container_names[container_type]
+ ".dbxml')";
}
else
{
query_string += "doc(\"dbxml:/"
+ container_names[container_type]
+ ".dbxml/"
+ *doc
+ "\")";
}
if (node_path != NULL)
query_string += *node_path;
XmlQueryContext context = m_manager->createQueryContext();
XmlQueryExpression qe;
XmlResults results;
try
{
qe = m_manager->prepare(query_string, context);
results = qe.execute(context);
}
catch (XmlException &xe)
{
debugOut() << "get node query string: " << query_string << endl;
debugOut() << "get_node in prepare xml exception: " << xe.what() << endl;
throw xe;
}
res.clear();
XmlValue value;
while (results.next(value))
{
res = value.asString();
}
return no_error;
}
///////////////////////////////////////////////////////////////////////////////
/// \brief
/// Packages the specified resource.
///
void MgLibraryResourceContentManager::PackageResource(MgResourceIdentifier& resource,
MgResourcePackageMaker& packageMaker)
{
ACE_ASSERT(resource.IsFolder());
MG_RESOURCE_SERVICE_TRY()
string resourcePathname;
MgUtil::WideCharToMultiByte(resource.ToString(), resourcePathname);
// Set up an XQuery.
XmlManager& xmlMan = m_container.getManager();
XmlQueryContext queryContext = xmlMan.createQueryContext();
string query;
if (m_repositoryMan.m_currUserIsAdmin)
{
queryContext.setEvaluationType(XmlQueryContext::Lazy);
query = "collection('";
}
else
{
queryContext.setEvaluationType(XmlQueryContext::Eager);
query = "for $i in collection('";
}
query += m_container.getName();
query += "')";
query += "/*[starts-with(dbxml:metadata('dbxml:name'),'";
query += resourcePathname;
if (m_repositoryMan.m_currUserIsAdmin)
{
query += "')]";
}
else
{
query += "')] order by dbxml:metadata('dbxml:name', $i) return $i";
}
// Execute the XQuery.
XmlResults results = IsTransacted() ?
xmlMan.query(GetXmlTxn(), query, queryContext, 0) :
xmlMan.query(query, queryContext, 0);
MgLibraryRepositoryManager& libraryRepositoryMan = (MgLibraryRepositoryManager&)m_repositoryMan;
MgResourceDataFileManager* dataFileMan = libraryRepositoryMan.GetResourceDataFileManager();
ACE_ASSERT(NULL != dataFileMan);
MgResourceDataStreamManager* dataStreamMan = libraryRepositoryMan.GetResourceDataStreamManager();
ACE_ASSERT(NULL != dataStreamMan);
// Get the resources
MgResourceIdentifier currResource;
XmlValue xmlValue;
while (results.next(xmlValue))
{
// Note that the permission checks were already done at the time we
// packaged the resource headers.
const XmlDocument& xmlDoc = xmlValue.asDocument();
currResource.SetResource(MgUtil::MultiByteToWideChar(xmlDoc.getName()));
// Package the resource content.
if (!packageMaker.PackageResourceContent(currResource, xmlDoc))
{
// The current user has no read permission to this resource.
continue;
}
// Skip packaging resource data if there is no resource tag.
XmlValue tagValue;
if (!xmlDoc.getMetaData(MgResourceInfo::sm_metadataUri,
MgResourceInfo::sm_metadataNames[MgResourceInfo::Tags], tagValue))
{
continue;
}
STRING resourceTags;
MgUtil::MultiByteToWideChar(tagValue.asString(), resourceTags);
// Get the file path if it exists.
MgTagManager tagMan(resourceTags);
STRING filePath;
MgTagInfo filePathTag;
if (tagMan.GetTag(MgResourceTag::DataFilePath, filePathTag, false))
{
filePath = dataFileMan->GetResourceDataFilePath();
filePath += filePathTag.GetAttribute(MgTagInfo::TokenValue);
filePath += L"/";
}
// Enumerate the resource data.
MgTagMap& tagMap = tagMan.GetTagMap();
for (MgTagMap::const_iterator i = tagMap.begin();
i != tagMap.end(); ++i)
{
CREFSTRING dataName = (*i).first;
// Skip the reserved tags.
if (tagMan.IsReservedTag(dataName))
{
continue;
}
// Get the resource data.
const MgTagInfo& tagInfo = (*i).second;
CREFSTRING mimeType = tagInfo.GetAttribute(MgTagInfo::MimeType);
CREFSTRING dataType = tagInfo.GetAttribute(MgTagInfo::StorageType);
Ptr<MgByteReader> byteReader;
if (MgResourceDataType::File == dataType)
{
ACE_ASSERT(!filePath.empty());
STRING pathname = filePath;
pathname += dataName;
byteReader = dataFileMan->GetResourceData(pathname, mimeType);
}
else if (MgResourceDataType::Stream == dataType)
{
string dataKey;
MgUtil::WideCharToMultiByte(
tagInfo.GetAttribute(MgTagInfo::TokenValue), dataKey);
byteReader = dataStreamMan->GetResourceData(dataKey, dataName,
mimeType);
}
else if (MgResourceDataType::String == dataType)
{
string data;
MgUtil::WideCharToMultiByte(
tagInfo.GetAttribute(MgTagInfo::TokenValue), data);
Ptr<MgByteSource> byteSource = new MgByteSource(
(BYTE_ARRAY_IN)data.c_str(), (INT32)data.length());
byteSource->SetMimeType(mimeType);
byteReader = byteSource->GetReader();
}
else
{
throw new MgInvalidResourceDataTypeException(
L"MgLibraryResourceContentManager.PackageResource",
__LINE__, __WFILE__, NULL, L"", NULL);
}
// Package the resource data.
packageMaker.PackageResourceData(currResource, byteReader,
dataName, dataType);
}
}
MG_RESOURCE_SERVICE_CATCH_AND_THROW(L"MgLibraryResourceContentManager.PackageResource")
}
