patch 9.0.0795: readblob() always reads the whole file
Problem: readblob() always reads the whole file.
Solution: Add arguments to read part of the file. (Ken Takata,
closes #11402)
diff --git a/src/blob.c b/src/blob.c
index a4e9981..92efb67 100644
--- a/src/blob.c
+++ b/src/blob.c
@@ -182,22 +182,52 @@
}
/*
- * Read "blob" from file "fd".
+ * Read blob from file "fd".
+ * Caller has allocated a blob in "rettv".
* Return OK or FAIL.
*/
int
-read_blob(FILE *fd, blob_T *blob)
+read_blob(FILE *fd, typval_T *rettv, off_T offset, off_T size_arg)
{
+ blob_T *blob = rettv->vval.v_blob;
struct stat st;
+ int whence;
+ off_T size = size_arg;
if (fstat(fileno(fd), &st) < 0)
+ return FAIL; // can't read the file, error
+
+ if (offset >= 0)
+ {
+ if (size == -1)
+ // size may become negative, checked below
+ size = st.st_size - offset;
+ whence = SEEK_SET;
+ }
+ else
+ {
+ if (size == -1)
+ size = -offset;
+ whence = SEEK_END;
+ }
+ // Trying to read bytes that aren't there results in an empty blob, not an
+ // error.
+ if (size < 0 || size > st.st_size)
+ return OK;
+ if (vim_fseek(fd, offset, whence) != 0)
+ return OK;
+
+ if (ga_grow(&blob->bv_ga, (int)size) == FAIL)
return FAIL;
- if (ga_grow(&blob->bv_ga, st.st_size) == FAIL)
- return FAIL;
- blob->bv_ga.ga_len = st.st_size;
+ blob->bv_ga.ga_len = (int)size;
if (fread(blob->bv_ga.ga_data, 1, blob->bv_ga.ga_len, fd)
< (size_t)blob->bv_ga.ga_len)
+ {
+ // An empty blob is returned on error.
+ blob_free(rettv->vval.v_blob);
+ rettv->vval.v_blob = NULL;
return FAIL;
+ }
return OK;
}