libsparse: add callback output file type
Add a new output file subclass that will call a callback for
each block as it is written. Will be used to measure the space
used by each sparse block to allow resparsing files.
Also add sparse_file_callback, which will write out a sparse
file by calling the provided write function.
Change-Id: I18707bd9c357b68da319cc07982e93d1c2b2bee2
diff --git a/libsparse/output_file.c b/libsparse/output_file.c
index 14b057a..dc56149 100644
--- a/libsparse/output_file.c
+++ b/libsparse/output_file.c
@@ -18,6 +18,7 @@
#define _LARGEFILE64_SOURCE 1
#include <fcntl.h>
+#include <limits.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdlib.h>
@@ -112,6 +113,15 @@
#define to_output_file_normal(_o) \
container_of((_o), struct output_file_normal, out)
+struct output_file_callback {
+ struct output_file out;
+ void *priv;
+ int (*write)(void *priv, const void *buf, int len);
+};
+
+#define to_output_file_callback(_o) \
+ container_of((_o), struct output_file_callback, out)
+
static int file_open(struct output_file *out, int fd)
{
struct output_file_normal *outn = to_output_file_normal(out);
@@ -262,6 +272,57 @@
.close = gz_file_close,
};
+static int callback_file_open(struct output_file *out, int fd)
+{
+ return 0;
+}
+
+static int callback_file_skip(struct output_file *out, int64_t off)
+{
+ struct output_file_callback *outc = to_output_file_callback(out);
+ int to_write;
+ int ret;
+
+ while (off > 0) {
+ to_write = min(off, (int64_t)INT_MAX);
+ ret = outc->write(outc->priv, NULL, to_write);
+ if (ret < 0) {
+ return ret;
+ }
+ off -= to_write;
+ }
+
+ return 0;
+}
+
+static int callback_file_pad(struct output_file *out, int64_t len)
+{
+ return -1;
+}
+
+static int callback_file_write(struct output_file *out, void *data, int len)
+{
+ int ret;
+ struct output_file_callback *outc = to_output_file_callback(out);
+
+ return outc->write(outc->priv, data, len);
+}
+
+static void callback_file_close(struct output_file *out)
+{
+ struct output_file_callback *outc = to_output_file_callback(out);
+
+ free(outc);
+}
+
+static struct output_file_ops callback_file_ops = {
+ .open = callback_file_open,
+ .skip = callback_file_skip,
+ .pad = callback_file_pad,
+ .write = callback_file_write,
+ .close = callback_file_close,
+};
+
int read_all(int fd, void *buf, size_t len)
{
size_t total = 0;
@@ -577,6 +638,32 @@
return &outn->out;
}
+struct output_file *open_output_callback(int (*write)(void *, const void *, int),
+ void *priv, unsigned int block_size, int64_t len, int gz, int sparse,
+ int chunks, int crc)
+{
+ int ret;
+ struct output_file_callback *outc;
+
+ outc = calloc(1, sizeof(struct output_file_callback));
+ if (!outc) {
+ error_errno("malloc struct outc");
+ return NULL;
+ }
+
+ outc->out.ops = &callback_file_ops;
+ outc->priv = priv;
+ outc->write = write;
+
+ ret = output_file_init(&outc->out, block_size, len, sparse, chunks, crc);
+ if (ret < 0) {
+ free(outc);
+ return NULL;
+ }
+
+ return &outc->out;
+}
+
struct output_file *open_output_fd(int fd, unsigned int block_size, int64_t len,
int gz, int sparse, int chunks, int crc)
{