Bring back old File C API (read-only currently)

This code path is not used anywhere in this commit, but aids in developing Lovr addons.

CMakeLists.txt

@@ -381,6 +381,7 @@ if(LOVR_ENABLE_FILESYSTEM)
   add_definitions(-DLOVR_ENABLE_FILESYSTEM)
   target_sources(lovr PRIVATE
     src/modules/filesystem/filesystem.c
+    src/modules/filesystem/file.c
     src/api/l_filesystem.c
   )
 endif()

src/modules/filesystem/file.c

@@ -0,0 +1,90 @@
+#include "filesystem/file.h"
+#include "filesystem/filesystem.h"
+#include "core/util.h"
+#include <stdlib.h>
+#include <string.h>
+
+// Currently only read operations are supported by File and all files are read into memory fully on open
+
+typedef struct {
+  uint8_t* data;
+  size_t offset;
+  size_t size;
+} FileInner;
+
+File* lovrFileInit(File* file ,const char* path) {
+  file->path = path;
+  file->handle = NULL;
+  file->mode = 0;
+  return file;
+}
+
+void lovrFileDestroy(void* ref) {
+  File* file = ref;
+  if (file->handle) {
+    lovrFileClose(ref);
+  }
+}
+
+bool lovrFileOpen(File* file, FileMode mode) {
+  lovrAssert(!file->handle, "File is already open");
+  file->mode = mode;
+
+  if (mode == OPEN_WRITE || mode == OPEN_APPEND)
+    return false;
+
+  FileInner *fileInner = malloc(sizeof(FileInner));
+  fileInner->offset = 0;
+  fileInner->data = lovrFilesystemRead(file->path, -1, &fileInner->size);
+  file->handle = fileInner;
+
+  if (!fileInner->data) {
+    fileInner->size = 0;
+    return false;
+  }
+
+  return true;
+}
+
+void lovrFileClose(File* file) {
+  lovrAssert(file->handle, "File must be open to close it");
+  FileInner *fileInner = (FileInner *)file->handle;
+  free(fileInner->data);
+  free(file->handle);
+  file->handle = NULL;
+}
+
+size_t lovrFileRead(File* file, void* data, size_t bytes) {
+  lovrAssert(file->handle && file->mode == OPEN_READ, "File must be open for reading");
+  FileInner *fileInner = (FileInner *)file->handle;
+  if (fileInner->offset + bytes > fileInner->size)
+    return 0;
+  memcpy(data, fileInner->data + fileInner->offset, bytes);
+  fileInner->offset += bytes;
+  return bytes;
+}
+
+size_t lovrFileWrite(File* file, const void* data, size_t bytes) {
+  lovrThrow("Writing not supported");
+}
+
+size_t lovrFileGetSize(File* file) {
+  lovrAssert(file->handle, "File must be open to get its size");
+  FileInner *fileInner = (FileInner *)file->handle;
+  return fileInner->size;
+}
+
+bool lovrFileSeek(File* file, size_t position) {
+  lovrAssert(file->handle, "File must be open to seek");
+  FileInner *fileInner = (FileInner *)file->handle;
+  if (position >= fileInner->size) // FIXME: Should seeking to fileInner->size exactly be allowed?
+    return false;
+  fileInner->offset = position;
+  return true;
+}
+
+size_t lovrFileTell(File* file) {
+  lovrAssert(file->handle, "File must be open to tell");
+  FileInner *fileInner = (FileInner *)file->handle;
+  return fileInner->offset;
+}

src/modules/filesystem/file.h

@@ -0,0 +1,26 @@
+#include <stdbool.h>
+#include <stddef.h>
+
+#pragma once
+
+typedef enum {
+  OPEN_READ,
+  OPEN_WRITE,
+  OPEN_APPEND
+} FileMode;
+
+typedef struct {
+  const char* path;
+  void* handle;
+  FileMode mode;
+} File;
+
+File* lovrFileInit(File* file, const char* filename);
+void lovrFileDestroy(void* ref);
+bool lovrFileOpen(File* file, FileMode mode);
+void lovrFileClose(File* file);
+size_t lovrFileRead(File* file, void* data, size_t bytes);
+size_t lovrFileWrite(File* file, const void* data, size_t bytes);
+size_t lovrFileGetSize(File* file);
+bool lovrFileSeek(File* file, size_t position);
+size_t lovrFileTell(File* file);