Initial palette support.

Part of #2. This adds the initial VFS directory implementation that
stores a set of palette files as .pngs in the user's config dir.

src/GNUmakefile

@@ -58,6 +58,7 @@ OBJS =                      \
     pager/hexdump.o         \
     pager/pager.o           \
     pager/plaintext.o       \
+    palette/palfs.o         \
     textures/actions.o      \
     textures/bundle.o       \
     textures/config.o       \

src/palette/palfs.c

@@ -0,0 +1,184 @@
+//
+// Copyright(C) 2024 Simon Howard
+//
+// You can redistribute and/or modify this program under the terms of
+// the GNU General Public License version 2 as published by the Free
+// Software Foundation, or any later version. This program is
+// distributed WITHOUT ANY WARRANTY; without even the implied warranty
+// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+
+#include <stdarg.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "fs/vfs.h"
+#include "common.h"
+#include "stringlib.h"
+
+#include "palette/palfs.h"
+
+struct palette_dir {
+	struct directory dir;
+	struct directory *inner;
+};
+
+static char *InnerName(const char *name)
+{
+	return StringJoin("", name, ".png", NULL);
+}
+
+static VFILE *PaletteFSOpen(void *dir, struct directory_entry *entry)
+{
+	struct palette_dir *pd = dir;
+	struct directory_entry *inner_ent =
+		VFS_EntryBySerial(pd->inner, entry->serial_no);
+
+	if (inner_ent == NULL) {
+		return NULL;
+	}
+
+	return VFS_OpenByEntry(pd->inner, inner_ent);
+}
+
+static struct directory *PaletteFSOpenDir(void *dir,
+                                          struct directory_entry *entry)
+{
+	if (entry == VFS_PARENT_DIRECTORY) {
+		// TODO
+	}
+
+	return NULL;
+}
+
+static void PaletteFSRefresh(void *dir, struct directory_entry **entries,
+                             size_t *num_entries)
+{
+	struct palette_dir *pd = dir;
+	int i;
+
+	VFS_Refresh(pd->inner);
+
+	*entries = checked_calloc(pd->inner->num_entries,
+	                          sizeof(struct directory_entry));
+	*num_entries = 0;
+
+	for (i = 0; i < pd->inner->num_entries; i++) {
+		struct directory_entry *inner_ent = &pd->inner->entries[i];
+		struct directory_entry *ent = &(*entries)[*num_entries];
+
+		if (inner_ent->type != FILE_TYPE_FILE
+		 || !StringHasSuffix(inner_ent->name, ".png")) {
+			continue;
+		}
+
+		ent->type = FILE_TYPE_FILE;
+		ent->name = checked_strdup(inner_ent->name);
+		*strstr(ent->name, ".png") = '\0';
+		ent->size = -1;
+		ent->serial_no = inner_ent->serial_no;
+
+		++*num_entries;
+	}
+}
+
+static void PaletteFSRemove(void *dir, struct directory_entry *entry)
+{
+	struct palette_dir *pd = dir;
+	struct directory_entry *inner_ent =
+		VFS_EntryBySerial(pd->inner, entry->serial_no);
+
+	if (inner_ent == NULL) {
+		return;
+	}
+
+	VFS_Remove(pd->inner, inner_ent);
+}
+
+static void PaletteFSRename(void *dir, struct directory_entry *entry,
+                            const char *new_name)
+{
+	struct palette_dir *pd = dir;
+	struct directory_entry *inner_ent =
+		VFS_EntryBySerial(pd->inner, entry->serial_no);
+	char *full_name;
+
+	if (inner_ent == NULL) {
+		return;
+	}
+
+	full_name = InnerName(new_name);
+	VFS_Rename(pd->inner, inner_ent, full_name);
+	free(full_name);
+}
+
+static void PaletteFSDescribeEntries(char *buf, size_t buf_len, int cnt)
+{
+	if (cnt == 1) {
+		snprintf(buf, buf_len, "1 palette");
+	} else {
+		snprintf(buf, buf_len, "%d palettes", cnt);
+	}
+}
+
+static void PaletteFSFree(void *dir)
+{
+	struct palette_dir *pd = dir;
+
+	VFS_CloseDir(pd->inner);
+}
+
+static const struct directory_funcs palette_fs_functions = {
+	PaletteFSRefresh,
+	PaletteFSOpen,
+	PaletteFSOpenDir,
+	PaletteFSRemove,
+	PaletteFSRename,
+	NULL, // need_commit
+	NULL, // commit
+	PaletteFSDescribeEntries,
+	NULL, // swap_entries
+	NULL, // save_snapshot
+	NULL, // restore_snapshot
+	PaletteFSFree,
+};
+
+static const char *GetPalettesPath(void)
+{
+	static char *result;
+	const char *home;
+
+	if (result != NULL) {
+		return result;
+	}
+
+	home = getenv("HOME");
+	assert(home != NULL);
+
+	result = MakeDirectories(home, ".config", "WadGadget",
+	                         "Palettes", NULL);
+	assert(result != NULL);
+	return result;
+}
+
+struct directory *PAL_OpenDirectory(void)
+{
+	struct palette_dir *pd = checked_calloc(1, sizeof(struct palette_dir));
+	const char *path = GetPalettesPath();
+	struct directory *inner;
+
+	inner = VFS_OpenDir(path);
+	if (inner == NULL) {
+		return NULL;
+	}
+
+	pd->dir.directory_funcs = &palette_fs_functions;
+	VFS_InitDirectory(&pd->dir, path);
+	pd->dir.type = FILE_TYPE_DIR;
+	pd->inner = inner;
+
+	PaletteFSRefresh(pd, &pd->dir.entries, &pd->dir.num_entries);
+
+	return &pd->dir;
+}

src/palette/palfs.h

@@ -0,0 +1,11 @@
+//
+// Copyright(C) 2024 Simon Howard
+//
+// You can redistribute and/or modify this program under the terms of
+// the GNU General Public License version 2 as published by the Free
+// Software Foundation, or any later version. This program is
+// distributed WITHOUT ANY WARRANTY; without even the implied warranty
+// of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+//
+
+struct directory *PAL_OpenDirectory(void);