pg_rewind: Replace the hybrid list+array data structure with simplehash.

Now that simplehash can be used in frontend code, let's make use of it.

Reviewed-by: Kyotaro Horiguchi, Soumyadeep Chakraborty
Discussion: https://www.postgresql.org/message-id/0c5b3783-af52-3ee5-f8fa-6e794061f70d%40iki.fi

Author: hlinnaka

src/bin/pg_rewind/copy_fetch.c

@@ -207,9 +207,9 @@ copy_executeFileMap(filemap_t *map)
 	file_entry_t *entry;
 	int			i;
 
-	for (i = 0; i < map->narray; i++)
+	for (i = 0; i < map->nentries; i++)
 	{
-		entry = map->array[i];
+		entry = map->entries[i];
 		execute_pagemap(&entry->target_pages_to_overwrite, entry->path);
 
 		switch (entry->action)

src/bin/pg_rewind/fetch.c

@@ -37,7 +37,7 @@ fetchSourceFileList(void)
  * Fetch all relation data files that are marked in the given data page map.
  */
 void
-executeFileMap(void)
+execute_file_actions(filemap_t *filemap)
 {
 	if (datadir_source)
 		copy_executeFileMap(filemap);

src/bin/pg_rewind/fetch.h

@@ -25,7 +25,7 @@
  */
 extern void fetchSourceFileList(void);
 extern char *fetchFile(const char *filename, size_t *filesize);
-extern void executeFileMap(void);
+extern void execute_file_actions(filemap_t *filemap);
 
 /* in libpq_fetch.c */
 extern void libpqProcessFileList(void);