Flipdot-display/src/esp32/display/font_store.cpp

#include "display/font_store.h"

#include <LittleFS.h>
#include <map>

#include "display/bitmap_store.h"
#include "logic/bitmap_format.h"
#include "logic/builtin_fonts.h"

static const char *DIR = "/fonts";
static const char *EXTENSION = ".fnt";

static uint32_t revision = 0;
// Loaded fonts by name; cleared when a font is saved or deleted
static std::map<String, std::vector<uint8_t>> cache;

static String path(const char *name)
{
	return String(DIR) + "/" + name + EXTENSION;
}

std::vector<FontInfo> listFonts()
{
	std::vector<FontInfo> list;
	for (int i = 0; i < BUILTIN_FONT_COUNT; i++)
		list.push_back({BUILTIN_FONTS[i].name, true, (uint8_t)fontHeight(builtinFont(BUILTIN_FONTS[i]))});
	for (const String &name : storedNames(DIR, EXTENSION))
		if (!findBuiltinFont(name.c_str()))
			list.push_back({name, false, (uint8_t)fontHeight(findFont(name.c_str()))});
	return list;
}

uint32_t fontListRevision()
{
	return revision;
}

bool fontExists(const char *name)
{
	if (findBuiltinFont(name))
		return true;
	return bitmapStorageAvailable() && validBitmapName(name) && LittleFS.exists(path(name));
}

Font findFont(const char *name)
{
	const BuiltinFont *builtin = findBuiltinFont(name);
	if (builtin)
		return builtinFont(*builtin);

	Font font;
	if (!bitmapStorageAvailable() || !validBitmapName(name))
		return font;
	auto cached = cache.find(name);
	if (cached == cache.end())
	{
		if (cache.size() >= 16)
			cache.clear();
		std::vector<uint8_t> data;
		File file;
		if (LittleFS.exists(path(name))) // open() logs an error for a missing file
			file = LittleFS.open(path(name), "r");
		if (file && file.size() <= FONT_MAX_SIZE)
		{
			data.resize(file.size());
			if (file.read(data.data(), data.size()) != data.size() || !validFont(data.data(), data.size()))
				data.clear();
		}
		if (file)
			file.close();
		cached = cache.emplace(name, std::move(data)).first; // also remembers a missing font
	}
	if (!cached->second.empty())
	{
		font.data = cached->second.data();
		font.size = cached->second.size();
	}
	return font;
}

const char *saveFont(const char *name, const uint8_t *data, size_t size)
{
	if (!validBitmapName(name))
		return "Invalid name: use 1-24 letters, digits, spaces, - or _";
	if (findBuiltinFont(name))
		return "A built-in font has this name";
	if (!validFont(data, size))
		return "Invalid font data";
	if (!bitmapStorageAvailable())
		return "No storage (install the new flash layout over USB, see README)";
	if (!LittleFS.exists(path(name)) && storedNames(DIR, EXTENSION).size() >= (size_t)MAX_FONTS)
		return "Too many fonts, delete some first";

	File file = LittleFS.open(path(name), "w");
	bool ok = file && file.write(data, size) == size;
	if (file)
		file.close();
	cache.clear();
	revision++;
	return ok ? nullptr : "Could not write the file (storage full?)";
}

const char *deleteFont(const char *name)
{
	if (findBuiltinFont(name))
		return "Built-in fonts can't be deleted";
	if (!bitmapStorageAvailable() || !validBitmapName(name) || !LittleFS.exists(path(name)))
		return "Font not found";
	if (!LittleFS.remove(path(name)))
		return "Could not delete the file";
	cache.clear();
	revision++;
	return nullptr;
}