libio: flip the meaning of the ostream_t sparse flag

Instead of "open sparse", make that the default and turn it into
a "no sparse" flag.

Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>

5 files changed, 34 insertions, 32 deletions

diff --git a/bin/rdsquashfs/src/fill_files.c b/bin/rdsquashfs/src/fill_files.c
index afc790e..372752a 100644
--- a/bin/rdsquashfs/src/fill_files.c
+++ b/bin/rdsquashfs/src/fill_files.c
@@ -142,7 +142,7 @@ static int fill_files(sqfs_data_reader_t *data, int flags)
 	openflags = OSTREAM_OPEN_OVERWRITE;
 
 	if (flags & UNPACK_NO_SPARSE)
-		openflags |= OSTREAM_OPEN_SPARSE;
+		openflags |= OSTREAM_OPEN_NO_SPARSE;
 
 	for (i = 0; i < num_files; ++i) {
 		fp = ostream_open_file(files[i].path, openflags);
diff --git a/bin/sqfsdiff/src/extract.c b/bin/sqfsdiff/src/extract.c
index 7e745cf..a956480 100644
--- a/bin/sqfsdiff/src/extract.c
+++ b/bin/sqfsdiff/src/extract.c
@@ -21,8 +21,7 @@ static int extract(sqfs_data_reader_t *data, const sqfs_inode_generic_t *inode,
 		return -1;
 	*ptr = '/';
 
-	fp = ostream_open_file(temp, OSTREAM_OPEN_OVERWRITE |
-			       OSTREAM_OPEN_SPARSE);
+	fp = ostream_open_file(temp, OSTREAM_OPEN_OVERWRITE);
 	if (fp == NULL) {
 		perror(temp);
 		return -1;
diff --git a/include/io/file.h b/include/io/file.h
index 44fd224..297047f 100644
--- a/include/io/file.h
+++ b/include/io/file.h
@@ -20,7 +20,7 @@ typedef int os_file_t;
 
 enum {
 	OSTREAM_OPEN_OVERWRITE = 0x01,
-	OSTREAM_OPEN_SPARSE = 0x02,
+	OSTREAM_OPEN_NO_SPARSE = 0x02,
 };
 
 #ifdef __cplusplus
@@ -48,9 +48,10 @@ SQFS_INTERNAL istream_t *istream_open_handle(const char *path, os_file_t fd);
  *
  * @memberof ostream_t
  *
- * If the flag OSTREAM_OPEN_SPARSE is set, the underlying implementation tries
- * to use seek/truncate style API to create sparse output files. If the flag
- * is not set, holes will always be filled with zero bytes.
+ * If the flag OSTREAM_OPEN_NO_SPARSE is set, the underlying implementation
+ * always writes chunks of zero bytes when passing a NULL pointer to append.
+ * Otherwise, it tries to use seek/truncate style APIs to create sparse output
+ * files.
  *
  * @param path The name to associate with the handle.
  * @param fd A native file handle.
@@ -81,9 +82,10 @@ SQFS_INTERNAL istream_t *istream_open_file(const char *path);
  * function fails, unless the flag OSTREAM_OPEN_OVERWRITE is set, in which
  * case the file is opened and its contents are discarded.
  *
- * If the flag OSTREAM_OPEN_SPARSE is set, the underlying implementation tries
- * to support sparse output files. If the flag is not set, holes will always
- * be filled with zero bytes.
+ * If the flag OSTREAM_OPEN_NO_SPARSE is set, the underlying implementation
+ * always writes chunks of zero bytes when passing a NULL pointer to append.
+ * Otherwise, it tries to use seek/truncate style APIs to create sparse output
+ * files.
  *
  * @param path A path to the file to open or create.
  * @param flags A combination of flags controling how to open/create the file.
diff --git a/lib/io/src/unix/ostream.c b/lib/io/src/unix/ostream.c
index 702a354..bc69f32 100644
--- a/lib/io/src/unix/ostream.c
+++ b/lib/io/src/unix/ostream.c
@@ -49,15 +49,7 @@ static int realize_sparse(file_ostream_t *file)
 	if (file->sparse_count == 0)
 		return 0;
 
-	if (file->flags & OSTREAM_OPEN_SPARSE) {
-		if (lseek(file->fd, file->sparse_count, SEEK_CUR) == (off_t)-1)
-			goto fail;
-
-		if (ftruncate(file->fd, file->size) != 0)
-			goto fail;
-
-		file->sparse_count = 0;
-	} else {
+	if (file->flags & OSTREAM_OPEN_NO_SPARSE) {
 		bufsz = file->sparse_count > 1024 ? 1024 : file->sparse_count;
 		buffer = calloc(1, bufsz);
 		if (buffer == NULL)
@@ -76,6 +68,14 @@ static int realize_sparse(file_ostream_t *file)
 		}
 
 		free(buffer);
+	} else {
+		if (lseek(file->fd, file->sparse_count, SEEK_CUR) == (off_t)-1)
+			goto fail;
+
+		if (ftruncate(file->fd, file->size) != 0)
+			goto fail;
+
+		file->sparse_count = 0;
 	}
 
 	return 0;
@@ -194,5 +194,6 @@ ostream_t *ostream_open_file(const char *path, int flags)
 
 ostream_t *ostream_open_stdout(void)
 {
-	return ostream_open_handle("stdout", STDOUT_FILENO, 0);
+	return ostream_open_handle("stdout", STDOUT_FILENO,
+				   OSTREAM_OPEN_NO_SPARSE);
 }
diff --git a/lib/io/src/win32/ostream.c b/lib/io/src/win32/ostream.c
index 9b488d8..edbefc7 100644
--- a/lib/io/src/win32/ostream.c
+++ b/lib/io/src/win32/ostream.c
@@ -43,17 +43,7 @@ static int realize_sparse(file_ostream_t *file)
 	if (file->sparse_count == 0)
 		return 0;
 
-	if (file->flags & OSTREAM_OPEN_SPARSE) {
-		pos.QuadPart = file->sparse_count;
-
-		if (!SetFilePointerEx(file->hnd, pos, NULL, FILE_CURRENT))
-			goto fail;
-
-		if (!SetEndOfFile(file->hnd))
-			goto fail;
-
-		file->sparse_count = 0;
-	} else {
+	if (file->flags & OSTREAM_OPEN_NO_SPARSE) {
 		bufsz = file->sparse_count > 1024 ? 1024 : file->sparse_count;
 		buffer = calloc(1, bufsz);
 
@@ -75,6 +65,16 @@ static int realize_sparse(file_ostream_t *file)
 		}
 
 		free(buffer);
+	} else {
+		pos.QuadPart = file->sparse_count;
+
+		if (!SetFilePointerEx(file->hnd, pos, NULL, FILE_CURRENT))
+			goto fail;
+
+		if (!SetEndOfFile(file->hnd))
+			goto fail;
+
+		file->sparse_count = 0;
 	}
 
 	return 0;
@@ -213,5 +213,5 @@ ostream_t *ostream_open_stdout(void)
 {
 	HANDLE hnd = GetStdHandle(STD_OUTPUT_HANDLE);
 
-	return ostream_open_handle("stdout", hnd, 0);
+	return ostream_open_handle("stdout", hnd, OSTREAM_OPEN_NO_SPARSE);
 }