Re: [PATCH 2/2] Print parser position on error

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Sascha,

On Monday 10 June 2013 15:56:01 Laurent Pinchart wrote:
> Hi Sascha,
> 
> I'm sorry for the late reply.
> 
> Great patch set, thank you. It's very helpful.

Should I got ahead and apply the patch with the proposed modifications below ?

> On Wednesday 08 May 2013 15:27:54 Sascha Hauer wrote:
> > Most parser functions take a **endp argument to indicate the caller
> > where parsing has stopped. This is currently only used after parsing
> > something successfully. This patch sets **endp to the erroneous
> > position in the error case and prints its position after an error
> > has occured.
> > 
> > Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
> > ---
> > 
> >  src/mediactl.c | 48 +++++++++++++++++++++++++++++++++++++++++++++---
> >  1 file changed, 45 insertions(+), 3 deletions(-)
> > 
> > diff --git a/src/mediactl.c b/src/mediactl.c
> > index c65de50..04ade15 100644
> > --- a/src/mediactl.c
> > +++ b/src/mediactl.c
> > @@ -40,6 +40,22 @@
> > 
> >  #include "mediactl.h"
> >  #include "tools.h"
> > 
> > +void media_print_streampos(struct media_device *media, const char *p,
> > const char *end)
> 
> The function can be static.
> 
> > +{
> > +	int pos;
> > +
> > +	pos = end - p + 1;
> > +
> > +	if (pos < 0)
> > +		pos = 0;
> > +	if (pos > strlen(p))
> > +		pos = strlen(p);
> > +
> > +	media_dbg(media, "\n");
> > +	media_dbg(media, " %s\n", p);
> > +	media_dbg(media, " %*s\n", pos, "^");
> > +}
> > +
> > 
> >  struct media_pad *media_entity_remote_source(struct media_pad *pad)
> >  {
> >  
> >  	unsigned int i;
> > 
> > @@ -538,12 +554,16 @@ struct media_pad *media_parse_pad(struct
> > media_device
> > *media, if (*p == '"') {
> > 
> >  		for (end = (char *)p + 1; *end && *end != '"'; ++end);
> >  		if (*end != '"') {
> > 
> > +			if (endp)
> > +				*endp = (char *)end;
> 
> No need to cast to a char * here, end is already a char *.
> 
> What would you think about adding
> 
> +       /* endp can be NULL. To avoid spreading NULL checks across the
> +        * function, set endp to &end in that case.
> +        */
> +       if (endp == NULL)
> +               endp = &end;
> 
> at the beginning of the function and removing the endp NULL checks that are
> spread across the code below ?
> 
> >  			media_dbg(media, "missing matching '\"'\n");
> >  			return NULL;
> >  		
> >  		}
> >  		
> >  		entity = media_get_entity_by_name(media, p + 1, end - p - 1);
> >  		if (entity == NULL) {
> > 
> > +			if (endp)
> > +				*endp = (char *)p + 1;
> > 
> >  			media_dbg(media, "no such entity \"%.*s\"\n", end - p - 1, p 
+
> 
> 1);
> 
> >  			return NULL;
> >  		
> >  		}
> > 
> > @@ -553,6 +573,8 @@ struct media_pad *media_parse_pad(struct media_device
> > *media, entity_id = strtoul(p, &end, 10);
> > 
> >  		entity = media_get_entity_by_id(media, entity_id);
> >  		if (entity == NULL) {
> > 
> > +			if (endp)
> > +				*endp = (char *)p;
> > 
> >  			media_dbg(media, "no such entity %d\n", entity_id);
> >  			return NULL;
> >  		
> >  		}
> > 
> > @@ -560,6 +582,8 @@ struct media_pad *media_parse_pad(struct media_device
> > *media, for (; isspace(*end); ++end);
> > 
> >  	if (*end != ':') {
> > 
> > +		if (endp)
> > +			*endp = end;
> > 
> >  		media_dbg(media, "Expected ':'\n", *end);
> >  		return NULL;
> >  	
> >  	}
> > 
> > @@ -569,6 +593,8 @@ struct media_pad *media_parse_pad(struct media_device
> > *media, pad = strtoul(p, &end, 10);
> > 
> >  	if (pad >= entity->info.pads) {
> > 
> > +		if (endp)
> > +			*endp = (char *)p;
> > 
> >  		media_dbg(media, "No pad '%d' on entity \"%s\". Maximum pad 
number is
> > 
> > %d\n", pad, entity->info.name, entity->info.pads - 1);
> > 
> >  		return NULL;
> > 
> > @@ -591,10 +617,15 @@ struct media_link *media_parse_link(struct
> > media_device *media, char *end;
> > 
> >  	source = media_parse_pad(media, p, &end);
> > 
> > -	if (source == NULL)
> > +	if (source == NULL) {
> > +		if (endp)
> > +			*endp = end;
> 
> The endp argument to media_parse_link() and media_parse_setup_link() is
> mandatory, there's no need to test it.
> 
> If you're fine with those modifications there's no need to resubmit the
> code, I'll fix it while applying.
> 
> >  		return NULL;
> > 
> > +	}
> > 
> >  	if (end[0] != '-' || end[1] != '>') {
> > 
> > +		if (endp)
> > +			*endp = end;
> > 
> >  		media_dbg(media, "Expected '->'\n");
> >  		return NULL;
> >  	
> >  	}
> > 
> > @@ -602,8 +633,11 @@ struct media_link *media_parse_link(struct
> > media_device *media, p = end + 2;
> > 
> >  	sink = media_parse_pad(media, p, &end);
> > 
> > -	if (sink == NULL)
> > +	if (sink == NULL) {
> > +		if (endp)
> > +			*endp = end;
> > 
> >  		return NULL;
> > 
> > +	}
> > 
> >  	*endp = end;
> > 
> > @@ -629,6 +663,8 @@ int media_parse_setup_link(struct media_device *media,
> > 
> >  	link = media_parse_link(media, p, &end);
> >  	if (link == NULL) {
> > 
> > +		if (endp)
> > +			*endp = end;
> > 
> >  		media_dbg(media,
> >  		
> >  			  "%s: Unable to parse link\n", __func__);
> >  		
> >  		return -EINVAL;
> > 
> > @@ -636,6 +672,8 @@ int media_parse_setup_link(struct media_device *media,
> > 
> >  	p = end;
> >  	if (*p++ != '[') {
> > 
> > +		if (endp)
> > +			*endp = (char *)p - 1;
> > 
> >  		media_dbg(media, "Unable to parse link flags: expected '['.\n");
> >  		return -EINVAL;
> >  	
> >  	}
> > 
> > @@ -643,6 +681,8 @@ int media_parse_setup_link(struct media_device *media,
> > 
> >  	flags = strtoul(p, &end, 10);
> >  	for (p = end; isspace(*p); p++);
> >  	if (*p++ != ']') {
> > 
> > +		if (endp)
> > +			*endp = (char *)p - 1;
> > 
> >  		media_dbg(media, "Unable to parse link flags: expected ']'.\n");
> >  		return -EINVAL;
> >  	
> >  	}
> > 
> > @@ -666,8 +706,10 @@ int media_parse_setup_links(struct media_device
> > *media, const char *p)
> > 
> >  	do {
> >  	
> >  		ret = media_parse_setup_link(media, p, &end);
> > 
> > -		if (ret < 0)
> > +		if (ret < 0) {
> > +			media_print_streampos(media, p, end);
> > 
> >  			return ret;
> > 
> > +		}
> > 
> >  		p = end + 1;
> >  	
> >  	} while (*end == ',');
-- 
Regards,

Laurent Pinchart