From dab511beb734f0cd87a585149636899f06369c5d Mon Sep 17 00:00:00 2001
From: Chris Frey <cdfrey@foursquare.net>
Date: Tue, 30 Nov 2010 22:07:00 -0500
Subject: [PATCH] lib: added DeviceBuilder class, which...

... gives a Builder interface for reading records directly from a device.
---
 ChangeLog        |  2 ++
 src/m_desktop.cc | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 src/m_desktop.h  | 69 +++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 157 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 9512b552..8966bdda 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -14,6 +14,8 @@ Release: version 0.17.0 - 2010/01/??
 	- lib: another API change, for Parser, removing StartParser()
 		and EndParser()
 	- lib: optimized Mode::DBLoader to allow application level data buffers
+	- lib: added DeviceBuilder class, which gives a Builder interface
+		to reading records directly from a device
 2010/11/16
 	- doc: clarified btool -X in its man page
 2010/11/09
diff --git a/src/m_desktop.cc b/src/m_desktop.cc
index f8120b7f..eb9c5b76 100644
--- a/src/m_desktop.cc
+++ b/src/m_desktop.cc
@@ -539,5 +539,92 @@ bool DBLoader::GetNextRecord(DBData &data)
 	return false;
 }
 
-}} // namespace Barry::Mode
+} // namespace Barry::Mode
+
+
+
+
+
+//////////////////////////////////////////////////////////////////////////////
+// DeviceBuilder class
+
+DeviceBuilder::DeviceBuilder(Mode::Desktop &desktop)
+	: m_desktop(desktop)
+	, m_loader(desktop)
+{
+}
+
+// searches the dbdb from the desktop to find the dbId,
+// returns false if not found, and adds it to the list of
+// databases to retrieve if found
+bool DeviceBuilder::Add(const std::string &dbname)
+{
+	try {
+		DBLabel id(m_desktop.GetDBID(dbname), dbname);
+		m_dbIds.push_back(id);
+		m_current = m_dbIds.begin();
+		return true;
+	}
+	catch( Barry::Error & ) {
+		// GetDBID() throws on error...
+		return false;
+	}
+}
+
+bool DeviceBuilder::BuildRecord(DBData &data,
+				size_t &offset,
+				const IConverter *ic)
+{
+	DBData temp;
+	if( !FetchRecord(temp, ic) )
+		return false;
+
+	// copy the metadata
+	data.SetVersion(temp.GetVersion());
+	data.SetDBName(temp.GetDBName());
+	data.SetIds(temp.GetRecType(), temp.GetUniqueId());
+	data.SetOffset(offset);
+
+	// copy data from temp into the given offset
+	size_t tempsize = temp.GetData().GetSize() - temp.GetOffset();
+	data.UseData().MemCpy(offset,
+		temp.GetData().GetData() + temp.GetOffset(), tempsize);
+	data.UseData().ReleaseBuffer(offset + tempsize);
+	return true;
+}
+
+bool DeviceBuilder::FetchRecord(DBData &data, const IConverter *ic)
+{
+	bool ret;
+
+	if( m_loader.IsBusy() ) {
+		ret = m_loader.GetNextRecord(data);
+	}
+	else {
+		// don't do anything if we're at the end of our rope
+		if( EndOfFile() )
+			return false;
+
+		// advance and check again... m_current always points
+		// to our current DB
+		++m_current;
+		if( EndOfFile() )
+			return false;
+
+		ret = m_loader.StartDBLoad(m_current->id, data);
+	}
+
+	// fill in the DBname if successful
+	if( ret ) {
+		data.SetDBName(m_current->name);
+	}
+	return ret;
+}
+
+bool DeviceBuilder::EndOfFile() const
+{
+	return m_current == m_dbIds.end();
+}
+
+} // namespace Barry
 
diff --git a/src/m_desktop.h b/src/m_desktop.h
index 3a63e375..dc84114a 100644
--- a/src/m_desktop.h
+++ b/src/m_desktop.h
@@ -27,12 +27,12 @@
 #include "data.h"
 #include "socket.h"
 #include "record.h"
+#include "builder.h"
 
 namespace Barry {
 
 // forward declarations
 class Parser;
-class Builder;
 class IConverter;
 
 namespace Mode {
@@ -165,7 +165,72 @@ public:
 	bool GetNextRecord(DBData &data);
 };
 
-}} // namespace Barry::Mode
+} // namespace Barry::Mode
+
+
+
+
+
+//
+// DeviceBuilder
+//
+/// Takes a list of database dbId's and behaves like a Builder,
+/// trying to avoid copies where possible on the device loading end.
+///
+class BXEXPORT DeviceBuilder : public Builder
+{
+	typedef unsigned int				dbid_type;
+
+	struct DBLabel
+	{
+		dbid_type id;
+		std::string name;
+
+		DBLabel(dbid_type id, const std::string &name)
+			: id(id)
+			, name(name)
+		{
+		}
+	};
+
+	typedef std::vector<DBLabel>			list_type;
+
+	// list of databases to fetch during build
+	list_type m_dbIds;
+	list_type::iterator m_current;
+
+	Mode::Desktop &m_desktop;
+
+	// loader object to use optimized batch loading while
+	// giving per-record control
+	Mode::DBLoader m_loader;
+
+public:
+	DeviceBuilder(Mode::Desktop &desktop);
+
+	// searches the dbdb from the desktop to find the dbId,
+	// returns false if not found, and adds it to the list of
+	// databases to retrieve if found
+	bool Add(const std::string &dbname);
+
+	/// sets the internal iterator to the start of the list
+	/// in order to perform a fresh run
+	void Restart() { m_current = m_dbIds.begin(); }
+
+	//
+	// Builder overrides
+	//
+
+	// has both BuildRecord() and Retrieve() functionality,
+	// and uses data all the way down to the socket level copy
+	virtual bool BuildRecord(DBData &data, size_t &offset,
+		const IConverter *ic);
+	virtual bool FetchRecord(DBData &data, const IConverter *ic);
+	virtual bool EndOfFile() const;
+};
+
+
+} // namespace Barry
 
 #endif
 
-- 
2.11.4.GIT