Implement error messages in the decoder side.

[apps/low-level-can-service.git] / pb_decode.c

diff --git a/pb_decode.c b/pb_decode.c
index 59efb3d..9d65504 100644 (file)
--- a/pb_decode.c
+++ b/pb_decode.c
@@ -39,10 +39,10 @@ static const pb_decoder_t PB_DECODERS[PB_LTYPES_COUNT] = {
 bool checkreturn pb_read(pb_istream_t *stream, uint8_t *buf, size_t count)
 {
     if (stream->bytes_left < count)
-        return false;
+        PB_RETURN_ERROR(stream, "end-of-stream");
     
     if (!stream->callback(stream, buf, count))
-        return false;
+        PB_RETURN_ERROR(stream, "io error");
     
     stream->bytes_left -= count;
     return true;
@@ -95,7 +95,7 @@ bool checkreturn pb_decode_varint(pb_istream_t *stream, uint64_t *dest)
             return true;
     }
     
-    return false;
+    PB_RETURN_ERROR(stream, "varint overflow");
 }
 
 bool checkreturn pb_skip_varint(pb_istream_t *stream)
@@ -152,7 +152,7 @@ bool checkreturn pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type)
         case PB_WT_64BIT: return pb_read(stream, NULL, 8);
         case PB_WT_STRING: return pb_skip_string(stream);
         case PB_WT_32BIT: return pb_read(stream, NULL, 4);
-        default: return false;
+        default: PB_RETURN_ERROR(stream, "invalid wire_type");
     }
 }
 
@@ -182,33 +182,33 @@ static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire
             *size = 4;
             return pb_read(stream, buf, 4);
         
-        default: return false;
+        default: PB_RETURN_ERROR(stream, "invalid wire_type");
     }
 }
 
-/* Decode string length from stream and return a substream with limited length. */
-static bool substream_callback(pb_istream_t *stream, uint8_t *buf, size_t count)
-{
-    pb_istream_t *parent = (pb_istream_t*)stream->state;
-    return pb_read(parent, buf, count);
-}
-
+/* Decode string length from stream and return a substream with limited length.
+ * Remember to close the substream using pb_close_string_substream().
+ */
 bool checkreturn pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream)
 {
     uint32_t size;
     if (!pb_decode_varint32(stream, &size))
         return false;
     
-    if (stream->bytes_left < size)
-        return false;
+    *substream = *stream;
+    if (substream->bytes_left < size)
+        PB_RETURN_ERROR(stream, "parent stream too short");
     
-    substream->callback = &substream_callback;
-    substream->state = stream;
     substream->bytes_left = size;
-    
+    stream->bytes_left -= size;
     return true;
 }
 
+void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream)
+{
+    stream->state = substream->state;
+}
+
 /* Iterator for pb_field_t list */
 typedef struct {
     const pb_field_t *start; /* Start of the pb_field_t array */
@@ -293,6 +293,7 @@ static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_t
                 && PB_LTYPE(iter->current->type) <= PB_LTYPE_LAST_PACKABLE)
             {
                 /* Packed array */
+                bool status;
                 size_t *size = (size_t*)iter->pSize;
                 pb_istream_t substream;
                 if (!pb_make_string_substream(stream, &substream))
@@ -305,7 +306,9 @@ static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_t
                         return false;
                     (*size)++;
                 }
-                return (substream.bytes_left == 0);
+                status = (substream.bytes_left == 0);
+                pb_close_string_substream(stream, &substream);
+                return status;
             }
             else
             {
@@ -313,7 +316,7 @@ static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_t
                 size_t *size = (size_t*)iter->pSize;
                 void *pItem = (uint8_t*)iter->pData + iter->current->data_size * (*size);
                 if (*size >= iter->current->array_size)
-                    return false;
+                    PB_RETURN_ERROR(stream, "array overflow");
                 
                 (*size)++;
                 return func(stream, iter->current, pItem);
@@ -336,9 +339,10 @@ static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_t
                 while (substream.bytes_left)
                 {
                     if (!pCallback->funcs.decode(&substream, iter->current, pCallback->arg))
-                        return false;
+                        PB_RETURN_ERROR(stream, "callback failed");
                 }
                 
+                pb_close_string_substream(stream, &substream);
                 return true;
             }
             else
@@ -360,7 +364,7 @@ static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_t
         }
         
         default:
-            return false;
+            PB_RETURN_ERROR(stream, "invalid field type");
     }
 }
 
@@ -459,7 +463,7 @@ bool checkreturn pb_decode(pb_istream_t *stream, const pb_field_t fields[], void
             iter.required_field_index < PB_MAX_REQUIRED_FIELDS &&
             !(fields_seen[iter.required_field_index >> 3] & (1 << (iter.required_field_index & 7))))
         {
-            return false;
+            PB_RETURN_ERROR(stream, "missing required field");
         }
     } while (pb_field_next(&iter));
     
@@ -535,7 +539,7 @@ bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, vo
         case 2: *(uint16_t*)dest = value; break;
         case 4: *(uint32_t*)dest = value; break;
         case 8: *(uint64_t*)dest = value; break;
-        default: return false;
+        default: PB_RETURN_ERROR(stream, "invalid data_size");
     }
     
     return status;
@@ -550,7 +554,7 @@ bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, v
     {
         case 4: *(int32_t*)dest = value; break;
         case 8: *(int64_t*)dest = value; break;
-        default: return false;
+        default: PB_RETURN_ERROR(stream, "invalid data_size");
     }
     
     return status;
@@ -579,7 +583,7 @@ bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, voi
     
     /* Check length, noting the space taken by the size_t header. */
     if (x->size > field->data_size - offsetof(pb_bytes_array_t, bytes))
-        return false;
+        PB_RETURN_ERROR(stream, "bytes overflow");
     
     return pb_read(stream, x->bytes, x->size);
 }
@@ -593,7 +597,7 @@ bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, vo
     
     /* Check length, noting the null terminator */
     if (size + 1 > field->data_size)
-        return false;
+        PB_RETURN_ERROR(stream, "string overflow");
     
     status = pb_read(stream, (uint8_t*)dest, size);
     *((uint8_t*)dest + size) = 0;
@@ -602,13 +606,16 @@ bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, vo
 
 bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
 {
+    bool status;
     pb_istream_t substream;
     
     if (!pb_make_string_substream(stream, &substream))
         return false;
     
     if (field->ptr == NULL)
-        return false;
+        PB_RETURN_ERROR(stream, "invalid field descriptor");
     
-    return pb_decode(&substream, (pb_field_t*)field->ptr, dest);
+    status = pb_decode(&substream, (pb_field_t*)field->ptr, dest);
+    pb_close_string_substream(stream, &substream);
+    return status;
 }