/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
/*
 * soup-converter-wrapper.c
 *
 * Copyright 2011 Red Hat, Inc.
 */

#include "config.h"

#include <string.h>

#include <glib/gi18n-lib.h>

#include "soup-converter-wrapper.h"
#include "soup.h"

/* SoupConverterWrapper is a GConverter that wraps another GConverter.
 * Mostly it is transparent, but it implements four special fallbacks
 * for Content-Encoding handling: (1) "deflate" can mean either raw
 * deflate or zlib-encoded deflate, (2) the server may mistakenly
 * claim that a response is encoded when actually it isn't, (3) the
 * response may contain trailing junk after the end of the encoded
 * portion that we want to ignore, (4) the response may be truncated
 * at an arbitrary point rather than containing a complete compressed
 * representation.
 *
 * If the wrapped conversion succeeds, then the wrapper will set the
 * %SOUP_MESSAGE_CONTENT_DECODED flag on its message.
 */

enum {
	PROP_0,
	PROP_BASE_CONVERTER,
	PROP_MESSAGE
};

struct _SoupConverterWrapperPrivate
{
	GConverter *base_converter;
	SoupMessage *msg;
	gboolean try_deflate_fallback;
	gboolean started;
	gboolean discarding;
};

static void soup_converter_wrapper_iface_init (GConverterIface *iface);

G_DEFINE_TYPE_WITH_CODE (SoupConverterWrapper, soup_converter_wrapper, G_TYPE_OBJECT,
                         G_ADD_PRIVATE (SoupConverterWrapper)
			 G_IMPLEMENT_INTERFACE (G_TYPE_CONVERTER,
						soup_converter_wrapper_iface_init))

static void
soup_converter_wrapper_init (SoupConverterWrapper *converter)
{
	converter->priv = soup_converter_wrapper_get_instance_private (converter);
}

static void
soup_converter_wrapper_finalize (GObject *object)
{
	SoupConverterWrapperPrivate *priv = SOUP_CONVERTER_WRAPPER (object)->priv;

	g_clear_object (&priv->base_converter);
	g_clear_object (&priv->msg);

	G_OBJECT_CLASS (soup_converter_wrapper_parent_class)->finalize (object);
}


static void
soup_converter_wrapper_set_property (GObject      *object,
				     guint         prop_id,
				     const GValue *value,
				     GParamSpec   *pspec)
{
	SoupConverterWrapperPrivate *priv = SOUP_CONVERTER_WRAPPER (object)->priv;

	switch (prop_id) {
	case PROP_BASE_CONVERTER:
		priv->base_converter = g_value_dup_object (value);
		if (G_IS_ZLIB_DECOMPRESSOR (priv->base_converter)) {
			GZlibCompressorFormat format;

			g_object_get (G_OBJECT (priv->base_converter),
				      "format", &format,
				      NULL);
			if (format == G_ZLIB_COMPRESSOR_FORMAT_ZLIB)
				priv->try_deflate_fallback = TRUE;
		}
		break;

	case PROP_MESSAGE:
		priv->msg = g_value_dup_object (value);
		break;

	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
		break;
	}
}

static void
soup_converter_wrapper_get_property (GObject    *object,
				     guint       prop_id,
				     GValue     *value,
				     GParamSpec *pspec)
{
	SoupConverterWrapperPrivate *priv = SOUP_CONVERTER_WRAPPER (object)->priv;

	switch (prop_id) {
	case PROP_BASE_CONVERTER:
		g_value_set_object (value, priv->base_converter);
		break;

	case PROP_MESSAGE:
		g_value_set_object (value, priv->msg);
		break;

	default:
		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
		break;
	}
}

static void
soup_converter_wrapper_class_init (SoupConverterWrapperClass *klass)
{
	GObjectClass *gobject_class = G_OBJECT_CLASS (klass);

	gobject_class->finalize = soup_converter_wrapper_finalize;
	gobject_class->get_property = soup_converter_wrapper_get_property;
	gobject_class->set_property = soup_converter_wrapper_set_property;

	g_object_class_install_property (gobject_class,
					 PROP_BASE_CONVERTER,
					 g_param_spec_object ("base-converter",
							      "Base GConverter",
							      "GConverter to wrap",
							      G_TYPE_CONVERTER,
							      G_PARAM_READWRITE |
							      G_PARAM_CONSTRUCT_ONLY |
							      G_PARAM_STATIC_STRINGS));
	g_object_class_install_property (gobject_class,
					 PROP_MESSAGE,
					 g_param_spec_object ("message",
							      "Message",
							      "Associated SoupMessage",
							      SOUP_TYPE_MESSAGE,
							      G_PARAM_READWRITE |
							      G_PARAM_CONSTRUCT_ONLY |
							      G_PARAM_STATIC_STRINGS));
}

GConverter *
soup_converter_wrapper_new (GConverter  *base_converter,
			    SoupMessage *msg)
{
	return g_object_new (SOUP_TYPE_CONVERTER_WRAPPER,
			     "base-converter", base_converter,
			     "message", msg,
			     NULL);
}

static void
soup_converter_wrapper_reset (GConverter *converter)
{
	SoupConverterWrapperPrivate *priv = SOUP_CONVERTER_WRAPPER (converter)->priv;

	if (priv->base_converter)
		g_converter_reset (priv->base_converter);
}

static GConverterResult
soup_converter_wrapper_fallback_convert (GConverter *converter,
					 const void *inbuf,
					 gsize       inbuf_size,
					 void       *outbuf,
					 gsize       outbuf_size,
					 GConverterFlags flags,
					 gsize      *bytes_read,
					 gsize      *bytes_written,
					 GError    **error)
{
	SoupConverterWrapperPrivate *priv = SOUP_CONVERTER_WRAPPER (converter)->priv;

	if (outbuf_size == 0) {
		g_set_error (error, G_IO_ERROR, G_IO_ERROR_NO_SPACE,
			     _("Output buffer is too small"));
		return G_CONVERTER_ERROR;
	}

	if (priv->discarding) {
		*bytes_read = inbuf_size;
		*bytes_written = 0;
	} else if (outbuf_size >= inbuf_size) {
		memcpy (outbuf, inbuf, inbuf_size);
		*bytes_read = *bytes_written = inbuf_size;
	} else {
		memcpy (outbuf, inbuf, outbuf_size);
		*bytes_read = *bytes_written = outbuf_size;
	}

	if (*bytes_read < inbuf_size)
		return G_CONVERTER_CONVERTED;

	if (flags & G_CONVERTER_INPUT_AT_END)
		return G_CONVERTER_FINISHED;
	else if (flags & G_CONVERTER_FLUSH)
		return G_CONVERTER_FLUSHED;
	else if (inbuf_size)
		return G_CONVERTER_CONVERTED;
	else {
		/* Force it to either read more input or
		 * try again with G_CONVERTER_INPUT_AT_END.
		 */
		g_set_error_literal (error, G_IO_ERROR,
				     G_IO_ERROR_PARTIAL_INPUT,
				     "");
		return G_CONVERTER_ERROR;
	}
}

static GConverterResult
soup_converter_wrapper_real_convert (GConverter *converter,
				     const void *inbuf,
				     gsize       inbuf_size,
				     void       *outbuf,
				     gsize       outbuf_size,
				     GConverterFlags flags,
				     gsize      *bytes_read,
				     gsize      *bytes_written,
				     GError    **error)
{
	SoupConverterWrapperPrivate *priv = SOUP_CONVERTER_WRAPPER (converter)->priv;
	GConverterResult result;
	GError *my_error = NULL;

 try_again:
	result = g_converter_convert (priv->base_converter,
				      inbuf, inbuf_size,
				      outbuf, outbuf_size,
				      flags, bytes_read, bytes_written,
				      &my_error);
	if (result != G_CONVERTER_ERROR) {
		if (!priv->started) {
			SoupMessageFlags message_flags = soup_message_get_flags (priv->msg);
			soup_message_set_flags (priv->msg, message_flags | SOUP_MESSAGE_CONTENT_DECODED);
			priv->started = TRUE;
		}

		if (result == G_CONVERTER_FINISHED &&
		    !(flags & G_CONVERTER_INPUT_AT_END)) {
			/* We need to keep reading (and discarding)
			 * input to the end of the message body.
			 */
			g_clear_object (&priv->base_converter);
			priv->discarding = TRUE;

			if (*bytes_written)
				return G_CONVERTER_CONVERTED;
			else {
				g_set_error_literal (error, G_IO_ERROR,
						     G_IO_ERROR_PARTIAL_INPUT,
						     "");
				return G_CONVERTER_ERROR;
			}
		}

		return result;
	}

	if (g_error_matches (my_error, G_IO_ERROR, G_IO_ERROR_PARTIAL_INPUT) &&
	    inbuf_size == 0 && (flags & G_CONVERTER_INPUT_AT_END)) {
		/* Server claimed compression but there was no message body. */
		g_error_free (my_error);
		*bytes_written = 0;
		return G_CONVERTER_FINISHED;
	}

	if (!g_error_matches (my_error, G_IO_ERROR, G_IO_ERROR_INVALID_DATA) ||
	    priv->started) {
		g_propagate_error (error, my_error);
		return result;
	}
	g_clear_error (&my_error);

	/* Deflate hack: some servers (especially Apache with
	 * mod_deflate) return raw compressed data without the zlib
	 * headers when the client claims to support deflate.
	 */
	if (priv->try_deflate_fallback) {
		priv->try_deflate_fallback = FALSE;
		g_object_unref (priv->base_converter);
		priv->base_converter = (GConverter *)
			g_zlib_decompressor_new (G_ZLIB_COMPRESSOR_FORMAT_RAW);
		goto try_again;
	}

	/* Passthrough hack: some servers mistakenly claim to be
	 * sending encoded data when in fact they aren't, so fall
	 * back to just not decoding.
	 */
	g_clear_object (&priv->base_converter);
	return soup_converter_wrapper_fallback_convert (converter,
							inbuf, inbuf_size,
							outbuf, outbuf_size,
							flags, bytes_read,
							bytes_written, error);
}

static GConverterResult
soup_converter_wrapper_convert (GConverter *converter,
				const void *inbuf,
				gsize       inbuf_size,
				void       *outbuf,
				gsize       outbuf_size,
				GConverterFlags flags,
				gsize      *bytes_read,
				gsize      *bytes_written,
				GError    **error)
{
	SoupConverterWrapperPrivate *priv = SOUP_CONVERTER_WRAPPER (converter)->priv;

	if (priv->base_converter) {
		return soup_converter_wrapper_real_convert (converter,
							    inbuf, inbuf_size,
							    outbuf, outbuf_size,
							    flags, bytes_read,
							    bytes_written, error);
	} else {
		return soup_converter_wrapper_fallback_convert (converter,
								inbuf, inbuf_size,
								outbuf, outbuf_size,
								flags, bytes_read,
								bytes_written, error);
	}
}

static void
soup_converter_wrapper_iface_init (GConverterIface *iface)
{
	iface->convert = soup_converter_wrapper_convert;
	iface->reset = soup_converter_wrapper_reset;
}