Initial sketch for a downloader object

src/core/downloader.c

@@ -0,0 +1,276 @@
+/*
+ * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stdlib.h>
+#include <errno.h>
+#include <gpxe/xfer.h>
+#include <gpxe/open.h>
+#include <gpxe/job.h>
+#include <gpxe/uaccess.h>
+#include <gpxe/umalloc.h>
+#include <gpxe/image.h>
+#include <gpxe/downloader.h>
+
+/** @file
+ *
+ * Image downloader
+ *
+ */
+
+/** A downloader */
+struct downloader {
+	/** Reference count for this object */
+	struct refcnt refcnt;
+
+	/** Job control interface */
+	struct job_interface job;
+	/** Data transfer interface */
+	struct xfer_interface xfer;
+
+	/** Image to contain downloaded file */
+	struct image *image;
+	/** Current position within image buffer */
+	size_t pos;
+	/** Image registration routine */
+	int ( * register_image ) ( struct image *image );
+};
+
+/**
+ * Terminate download
+ *
+ * @v downloader	Downloader
+ * @v rc		Reason for termination
+ */
+static void downloader_finished ( struct downloader *downloader, int rc ) {
+
+	/* Block further incoming messages */
+	job_nullify ( &downloader->job );
+	xfer_nullify ( &downloader->xfer );
+
+	/* Free resources and close interfaces */
+	image_put ( downloader->image );
+	xfer_close ( &downloader->xfer, rc );
+	job_done ( &downloader->job, rc );
+
+	/* Drop reference to self */
+	ref_put ( &downloader->refcnt );
+}
+
+/**
+ * Ensure that download buffer is large enough for the specified size
+ *
+ * @v downloader	Downloader
+ * @v len		Required minimum size
+ * @ret rc		Return status code
+ */
+static int downloader_ensure_size ( struct downloader *downloader,
+				    size_t len ) {
+	userptr_t new_buffer;
+
+	/* If buffer is already large enough, do nothing */
+	if ( len <= downloader->image->len )
+		return 0;
+
+	/* Extend buffer */
+	new_buffer = urealloc ( downloader->image->data, len );
+	if ( ! new_buffer ) {
+		DBGC ( downloader, "Downloader %p could not extend buffer to "
+		       "%zd bytes\n", downloader, len );
+		return -ENOBUFS;
+	}
+	downloader->image->data = new_buffer;
+	downloader->image->len = len;
+
+	return 0;
+}
+
+/****************************************************************************
+ *
+ * Job control interface
+ *
+ */
+
+/**
+ * Handle start() event received via job control interface
+ *
+ * @v job		Downloader job control interface
+ */
+static void downloader_job_start ( struct job_interface *job ) {
+	struct downloader *downloader = 
+		container_of ( job, struct downloader, job );
+
+	/* Start data transfer */
+	xfer_start ( &downloader->xfer );
+}
+
+/**
+ * Handle kill() event received via job control interface
+ *
+ * @v job		Downloader job control interface
+ */
+static void downloader_job_kill ( struct job_interface *job ) {
+	struct downloader *downloader = 
+		container_of ( job, struct downloader, job );
+
+	/* Terminate download */
+	downloader_finished ( downloader, -ECANCELED );
+}
+
+/** Downloader job control interface operations */
+static struct job_interface_operations downloader_job_operations = {
+	.start		= downloader_job_start,
+	.done		= ignore_job_done,
+	.kill		= downloader_job_kill,
+	.progress	= ignore_job_progress,
+};
+
+/****************************************************************************
+ *
+ * Data transfer interface
+ *
+ */
+
+/**
+ * Handle seek() event received via data transfer interface
+ *
+ * @v xfer		Downloader data transfer interface
+ * @v pos		New position
+ * @ret rc		Return status code
+ */
+static int downloader_xfer_seek ( struct xfer_interface *xfer, size_t pos ) {
+	struct downloader *downloader =
+		container_of ( xfer, struct downloader, xfer );
+	int rc;
+
+	/* Ensure that we have enough buffer space for this buffer position */
+	if ( ( rc = downloader_ensure_size ( downloader, pos ) ) != 0 )
+		return rc;
+
+	/* Update current buffer position */
+	downloader->pos = pos;
+
+	return 0;
+}
+
+/**
+ * Handle deliver_raw() event received via data transfer interface
+ *
+ * @v xfer		Downloader data transfer interface
+ * @v data		Data buffer
+ * @v len		Length of data buffer
+ * @ret rc		Return status code
+ */
+static int downloader_xfer_deliver_raw ( struct xfer_interface *xfer,
+					 const void *data, size_t len ) {
+	struct downloader *downloader =
+		container_of ( xfer, struct downloader, xfer );
+	size_t max;
+	int rc;
+
+	/* Ensure that we have enough buffer space for this data */
+	max = ( downloader->pos + len );
+	if ( ( rc = downloader_ensure_size ( downloader, max ) ) != 0 )
+		return rc;
+
+	/* Copy data to buffer */
+	copy_to_user ( downloader->image->data, downloader->pos, data, len );
+
+	/* Update current buffer position */
+	downloader->pos += len;
+
+	return 0;
+}
+
+/**
+ * Handle close() event received via data transfer interface
+ *
+ * @v xfer		Downloader data transfer interface
+ * @v rc		Reason for close
+ */
+static void downloader_xfer_close ( struct xfer_interface *xfer, int rc ) {
+	struct downloader *downloader =
+		container_of ( xfer, struct downloader, xfer );
+
+	/* Register image if download was successful */
+	if ( rc == 0 )
+		rc = downloader->register_image ( downloader->image );
+
+	/* Terminate download */
+	downloader_finished ( downloader, rc );
+}
+
+/** Downloader data transfer interface operations */
+static struct xfer_interface_operations downloader_xfer_operations = {
+	.start		= ignore_xfer_start,
+	.close		= downloader_xfer_close,
+	.vredirect	= default_xfer_vredirect,
+	.seek		= downloader_xfer_seek,
+	.deliver	= xfer_deliver_as_raw,
+	.deliver_raw	= downloader_xfer_deliver_raw,
+};
+
+/****************************************************************************
+ *
+ * Instantiator
+ *
+ */
+
+/**
+ * Instantiate a downloader
+ *
+ * @v job		Job control interface
+ * @v uri_string	URI string
+ * @v image		Image to fill with downloaded file
+ * @v register_image	Image registration routine
+ * @ret rc		Return status code
+ *
+ * Instantiates a downloader object to download the specified URI into
+ * the specified image object.  If the download is successful, the
+ * image registration routine @c register_image() will be called.
+ */
+int create_downloader ( struct job_interface *job, const char *uri_string,
+			struct image *image,
+			int ( * register_image ) ( struct image *image ) ) {
+	struct downloader *downloader;
+	int rc;
+
+	/* Allocate and initialise structure */
+	downloader = malloc ( sizeof ( *downloader ) );
+	if ( ! downloader )
+		return -ENOMEM;
+	memset ( downloader, 0, sizeof ( *downloader ) );
+	job_init ( &downloader->job, &downloader_job_operations,
+		   &downloader->refcnt );
+	xfer_init ( &downloader->xfer, &downloader_xfer_operations,
+		    &downloader->refcnt );
+	downloader->image = image_get ( image );
+	downloader->register_image = register_image;
+
+	/* Instantiate child objects and attach to our interfaces */
+	if ( ( rc = open ( &downloader->xfer, LOCATION_URI,
+			   uri_string ) ) != 0 )
+		goto err;
+
+	/* Attach parent interface and return */
+	job_plug_plug ( &downloader->job, job );
+	return 0;
+
+ err:
+	downloader_finished ( downloader, rc );
+	return rc;
+}

src/include/gpxe/downloader.h

@@ -0,0 +1,17 @@
+#ifndef _GPXE_DOWNLOADER_H
+#define _GPXE_DOWNLOADER_H
+
+/** @file
+ *
+ * Image downloader
+ *
+ */
+
+struct job_interface;
+struct image;
+
+extern int create_downloader ( struct job_interface *job,
+			       const char *uri_string, struct image *image,
+			       int ( * register_image ) ( struct image * ) );
+
+#endif /* _GPXE_DOWNLOADER_H */