DMS: implemented full information file with JSON formatted comments

src/obidms.h

@@ -75,6 +75,25 @@ typedef struct Opened_indexers_list {
 } Opened_indexers_list_t, *Opened_indexers_list_p;
 
 
+/**
+ * @brief A structure stored in an information file and containing comments and additional informations on the DMS
+ * including the command line history.
+ *
+ * A pointer on the comments is kept in the OBIDMS structure when a DMS is opened.
+ */
+typedef struct OBIDMS_infos {
+	bool	                little_endian;                  	/** Whether the DMS is in little endian.
+																 */
+	size_t                  file_size;                          /** The size of the file in bytes.
+																 */
+	size_t			     	used_size;    						/**< Used size in bytes.
+	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 */
+	char 			    	comments[];							/**< Comments, additional informations on the DMS including
+																 *   the command line history.
+ 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 */
+} OBIDMS_infos_t, *OBIDMS_infos_p;
+
+
 /**
  * @brief A structure describing an OBIDMS instance
  *
@@ -114,12 +133,12 @@ typedef struct OBIDMS {
 	int						tax_dir_fd;							/**< The file descriptor of the directory entry
 																 *   usable to refer and scan the taxonomy directory.
 																 */
-	bool					little_endian;						/**< Endianness of the database.
-	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 */
 	Opened_columns_list_p 	opened_columns;						/**< List of opened columns.
 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 */
 	Opened_indexers_list_p 	opened_indexers;					/**< List of opened indexers.
 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 */
+	OBIDMS_infos_p 			infos;							    /**< A pointer on the mapped DMS information file.
+ 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 	 */
 } OBIDMS_t, *OBIDMS_p;
 
 
@@ -239,6 +258,44 @@ OBIDMS_p obi_dms(const char* dms_path);
 int obi_close_dms(OBIDMS_p dms, bool force);
 
 
+/**
+ * @brief Internal function writing new comments in a DMS informations file.
+ *
+ * The new comments replace the pre-existing ones.
+ * The informations file is enlarged if necessary.
+ *
+ * @param dms A pointer on the DMS.
+ * @param comments The new comments that should be written.
+ *
+ * @retval 0 if the operation was successfully completed.
+ * @retval -1 if an error occurred.
+ *
+ * @since September 2018
+ * @author Celine Mercier (celine.mercier@metabarcoding.org)
+ */
+int obi_dms_write_comments(OBIDMS_p dms, const char* comments);
+
+
+/**
+ * @brief Adds comments to a DMS informations file.
+ *
+ * This reads the comments in the JSON format and adds the key value pair.
+ * If the key already exists, the value format is turned into an array and the new value is appended
+ * if it is not already in the array.
+ *
+ * @param column A pointer on an OBIDMS column.
+ * @param key The key.
+ * @param value The value associated with the key.
+ *
+ * @retval 0 if the operation was successfully completed.
+ * @retval -1 if an error occurred.
+ *
+ * @since September 2018
+ * @author Celine Mercier (celine.mercier@metabarcoding.org)
+ */
+int obi_dms_add_comment(OBIDMS_p dms, const char* key, const char* value);
+
+
 /**
  * @brief Returns a column identified by its name and its version number from the list of opened columns.
  *