Migration to iso_file_src in file writing function.

libisofs/file_src.c

@@ -1,3 +1,10 @@
+/*
+ * Implementation of iso_file_src for:
+ * 
+ * a) read from local filesystem files
+ * b) read from previous session / image files
+ */
+
 #include <stdlib.h>       
 #include <stdio.h>       
 #include <sys/types.h>
@@ -10,9 +17,24 @@
 
 #include "file_src.h"
 #include "messages.h"
+#include "libisofs.h"
+#include "util.h"
 
 #define BLOCK_SIZE 2048
 
+
+void iso_file_src_free(struct iso_file_src *src)
+{
+	src->free_data(src);
+	free(src);
+}
+
+/*
+ * ==========================================================================
+ * A) FILE SRC FOR LOCAL FILESYSTEM FILES
+ * ==========================================================================
+ */
+
 struct local_file_data {
 	int fd; /* the file descriptor, once the file is opened */
 	off_t size; /* file size */
@@ -117,7 +139,10 @@ off_t lf_get_size(struct iso_file_src *src)
 static
 void lf_free_data(struct iso_file_src *src)
 {
-	free(src->data);
+	struct local_file_data *data;
+	data = (struct local_file_data*) src->data;
+	free(data->path);
+	free(data);
 }
 
 struct iso_file_src* 
@@ -161,3 +186,121 @@ iso_file_src_from_path(const char *path)
 	src->data = data;
 	return src;
 }
+
+
+/*
+ * ==========================================================================
+ * B) FILE SRC FOR PREVIOUS IMAGE FILES
+ * ==========================================================================
+ */
+
+struct prev_img_file_data {
+	int block; /* block where image begins */
+	off_t size; /* file size */
+	int nblocks; /* file size in blocks */
+	int current; /* last block read from file */
+	int error;
+	struct data_source *src; /* source for reading from previous image */
+};
+
+static
+int pi_open(struct iso_file_src *src)
+{
+	struct prev_img_file_data *data;
+	assert(src);
+	
+	data = (struct prev_img_file_data*) src->data;
+	data->current = data->block;
+	data->error = 0;
+	return 1;
+}
+
+static
+void pi_close(struct iso_file_src *src)
+{
+	/* nothing needed */
+	return;
+}
+
+static
+int pi_read_block(struct iso_file_src *src, unsigned char *buffer)
+{
+	int res;
+	struct prev_img_file_data *data;
+	assert(src);
+	assert(buffer);
+	
+	data = (struct prev_img_file_data*) src->data;
+	
+	if (data->current >= data->block + data->nblocks) {
+		return 0;
+	}
+	
+	if (data->error) {
+		memset(buffer, 0, BLOCK_SIZE);
+		data->current++;
+		return -2;
+	}
+	
+	res = data->src->read_block(data->src, data->current++, buffer);
+	if (res < 0) {
+		iso_msg_sorry(LIBISO_CANT_READ_IMG, 
+			"Problem reading file from previous image");
+		/* fill buffer with 0s and return */ 
+		memset(buffer, 0, BLOCK_SIZE);
+		return -1;
+	} 
+	
+	if (data->current >= data->block + data->nblocks) {
+		return 0;
+	} else {
+		return 1;
+	}
+}
+
+static
+off_t pi_get_size(struct iso_file_src *src)
+{
+	struct prev_img_file_data *data;
+	assert(src);
+	
+	data = (struct prev_img_file_data*) src->data;
+	return data->size;
+}
+
+static
+void pi_free_data(struct iso_file_src *src)
+{
+	free(src->data);
+}
+
+struct iso_file_src* 
+iso_file_src_from_prev_img(struct data_source* data_src, int block, off_t size)
+{
+	struct iso_file_src *src;
+	struct prev_img_file_data *data;
+	
+	data = malloc(sizeof(struct prev_img_file_data));
+	if (!data)
+		return NULL;
+	
+	src = malloc(sizeof(struct iso_file_src));	
+	if (!src) {
+		free(data);
+		return NULL;
+	}
+	
+	data->block = block;
+	data->size = size;
+	data->nblocks = div_up(size, BLOCK_SIZE);
+	data->src = data_src;
+	
+	src->open = pi_open;
+	src->close = pi_close;
+	src->read_block = pi_read_block;
+	src->get_size = pi_get_size;
+	src->free_data = pi_free_data;
+	
+	src->data = data;
+	return src;
+}