libio: Add a function to open an istream_t from a directory iterator

For the native versions, this is currently dummied out, always returning
an error number. The idea is to laster wrap the libtar interface around
a directory iterator, here we need that method to support the existing
use case in tar2sqfs.

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

4 files changed, 45 insertions, 0 deletions

diff --git a/include/io/dir_iterator.h b/include/io/dir_iterator.h
index 60c3796..b7212b3 100644
--- a/include/io/dir_iterator.h
+++ b/include/io/dir_iterator.h
@@ -8,6 +8,7 @@
 #define IO_DIR_ITERATOR_H
 
 #include "sqfs/predef.h"
+#include "io/istream.h"
 
 /**
  * @struct dir_entry_t
@@ -136,6 +137,19 @@ typedef struct dir_iterator_t {
 	 * @param it A pointer to the iterator itself.
 	 */
 	void (*ignore_subdir)(struct dir_iterator_t *it);
+
+	/**
+	 * @brief If the last entry was a regular file, open it.
+	 *
+	 * If next() returned a file, this can be used to create an istream
+	 * to read from it.
+	 *
+	 * @param it A pointer to the iterator itself.
+	 * @param out Returns a pointer to a @ref istream_t on success.
+	 *
+	 * @return Zero on success, negative @ref SQFS_ERROR value on failure.
+	 */
+	int (*open_file_ro)(struct dir_iterator_t *it, istream_t **out);
 } dir_iterator_t;
 
 enum {
diff --git a/lib/io/src/dir_tree_iterator.c b/lib/io/src/dir_tree_iterator.c
index 604efd5..67d33c3 100644
--- a/lib/io/src/dir_tree_iterator.c
+++ b/lib/io/src/dir_tree_iterator.c
@@ -272,6 +272,18 @@ static void ignore_subdir(dir_iterator_t *base)
 	pop(it);
 }
 
+static int open_file_ro(dir_iterator_t *base, istream_t **out)
+{
+	dir_tree_iterator_t *it = (dir_tree_iterator_t *)base;
+
+	if (it->top == NULL) {
+		*out = NULL;
+		return SQFS_ERROR_NO_ENTRY;
+	}
+
+	return it->top->dir->open_file_ro(it->top->dir, out);
+}
+
 dir_iterator_t *dir_tree_iterator_create(const char *path,
 					 const dir_tree_cfg_t *cfg)
 {
@@ -303,6 +315,7 @@ dir_iterator_t *dir_tree_iterator_create(const char *path,
 	((dir_iterator_t *)it)->read_link = read_link;
 	((dir_iterator_t *)it)->open_subdir = open_subdir;
 	((dir_iterator_t *)it)->ignore_subdir = ignore_subdir;
+	((dir_iterator_t *)it)->open_file_ro = open_file_ro;
 
 	return (dir_iterator_t *)it;
 fail:
diff --git a/lib/io/src/unix/dir_iterator.c b/lib/io/src/unix/dir_iterator.c
index d2727ad..8d30b3f 100644
--- a/lib/io/src/unix/dir_iterator.c
+++ b/lib/io/src/unix/dir_iterator.c
@@ -126,6 +126,13 @@ static void dir_ignore_subdir(dir_iterator_t *it)
 	(void)it;
 }
 
+static int dir_open_file_ro(dir_iterator_t *it, istream_t **out)
+{
+	(void)it;
+	*out = NULL;
+	return SQFS_ERROR_UNSUPPORTED;
+}
+
 static int dir_open_subdir(dir_iterator_t *base, dir_iterator_t **out)
 {
 	const unix_dir_iterator_t *it = (const unix_dir_iterator_t *)base;
@@ -166,6 +173,7 @@ static int dir_open_subdir(dir_iterator_t *base, dir_iterator_t **out)
 	((dir_iterator_t *)sub)->read_link = dir_read_link;
 	((dir_iterator_t *)sub)->open_subdir = dir_open_subdir;
 	((dir_iterator_t *)sub)->ignore_subdir = dir_ignore_subdir;
+	((dir_iterator_t *)sub)->open_file_ro = dir_open_file_ro;
 
 	*out = (dir_iterator_t *)sub;
 	return 0;
@@ -206,6 +214,7 @@ dir_iterator_t *dir_iterator_create(const char *path)
 	((dir_iterator_t *)it)->read_link = dir_read_link;
 	((dir_iterator_t *)it)->open_subdir = dir_open_subdir;
 	((dir_iterator_t *)it)->ignore_subdir = dir_ignore_subdir;
+	((dir_iterator_t *)it)->open_file_ro = dir_open_file_ro;
 
 	return (dir_iterator_t *)it;
 }
diff --git a/lib/io/src/win32/dir_iterator.c b/lib/io/src/win32/dir_iterator.c
index 94fd6e6..d8ac8f3 100644
--- a/lib/io/src/win32/dir_iterator.c
+++ b/lib/io/src/win32/dir_iterator.c
@@ -112,6 +112,13 @@ static void dir_iterator_ignore_subdir(dir_iterator_t *it)
 	(void)it;
 }
 
+static int dir_iterator_open_file_ro(dir_iterator_t *it, istream_t **out)
+{
+	(void)it;
+	*out = NULL;
+	return SQFS_ERROR_UNSUPPORTED;
+}
+
 static int dir_iterator_open_subdir(dir_iterator_t *it, dir_iterator_t **out)
 {
 	const dir_iterator_win32_t *dir = (const dir_iterator_win32_t *)it;
@@ -145,6 +152,7 @@ static int dir_iterator_open_subdir(dir_iterator_t *it, dir_iterator_t **out)
 	((dir_iterator_t *)sub)->read_link = dir_iterator_read_link;
 	((dir_iterator_t *)sub)->open_subdir = dir_iterator_open_subdir;
 	((dir_iterator_t *)sub)->ignore_subdir = dir_iterator_ignore_subdir;
+	((dir_iterator_t *)sub)->open_file_ro = dir_iterator_open_file_ro;
 	sub->is_first = true;
 	sub->state = 0;
 
@@ -205,6 +213,7 @@ dir_iterator_t *dir_iterator_create(const char *path)
 	((dir_iterator_t *)it)->read_link = dir_iterator_read_link;
 	((dir_iterator_t *)it)->open_subdir = dir_iterator_open_subdir;
 	((dir_iterator_t *)it)->ignore_subdir = dir_iterator_ignore_subdir;
+	((dir_iterator_t *)it)->open_file_ro = dir_iterator_open_file_ro;
 	it->is_first = true;
 	it->state = 0;