FBT/SDK: New app flag UnloadAssetPacks to free RAM (#260)

* Store app flags in FAP header

* Add app flag to UnloadAssetPacks to free RAM

* Unload asset packs in NFC and MFKey

* Clearer size units

* Update changelog

* Future proof logic

* Sync apps

scripts/fbt/elfmanifest.py

@@ -1,5 +1,6 @@
 import os
 import struct
+from enum import IntFlag
 from dataclasses import dataclass, field
 
 from flipper.assets.icon import file2image
@@ -9,6 +10,13 @@ from .appmanifest import FlipperApplication
 _MANIFEST_MAGIC = 0x52474448
 
 
+class ElfManifestFlag(IntFlag):
+    Default = 0
+    InsomniaSafe = 1 << 0
+
+    UnloadAssetPacks = 1 << 7
+
+
 @dataclass
 class ElfManifestBaseHeader:
     manifest_version: int
@@ -45,6 +53,26 @@ class ElfManifestV1:
         )
 
 
+@dataclass
+class ElfManifestV1Ext:
+    stack_size: int
+    app_version: int
+    name: str = ""
+    icon: bytes = field(default=b"")
+    flags: int = ElfManifestFlag.Default
+
+    def as_bytes(self):
+        return struct.pack(
+            "<hI32s?32sB",
+            self.stack_size,
+            self.app_version,
+            bytes(self.name.encode("ascii")),
+            bool(self.icon),
+            self.icon,
+            self.flags,
+        )
+
+
 def assemble_manifest_data(
     app_manifest: FlipperApplication,
     hardware_target: int,
@@ -67,16 +95,21 @@ def assemble_manifest_data(
         app_manifest.fap_version[1] & 0xFFFF
     )
 
+    flags_as_int = ElfManifestFlag.Default
+    for flag in app_manifest.flags:
+        flags_as_int |= ElfManifestFlag[flag]
+
     data = ElfManifestBaseHeader(
         manifest_version=1,
         api_version=sdk_version,
         hardware_target_id=hardware_target,
     ).as_bytes()
-    data += ElfManifestV1(
+    data += ElfManifestV1Ext(
         stack_size=app_manifest.stack_size,
         app_version=app_version_as_int,
         name=app_manifest.name,
         icon=image_data,
+        flags=flags_as_int,
     ).as_bytes()
 
     return data

scripts/fbt_tools/fbt_apps.py

@@ -69,8 +69,7 @@ class ApplicationsCGenerator:
     {{
      .name = "{app.name}",
      .icon = {f"&{app.icon}" if app.icon else "NULL"},
-     .path = "{app_path}",
-     .flags = {'|'.join(f"FlipperApplicationFlag{flag}" for flag in app.flags)} }}"""
+     .path = "{app_path}" }}"""
 
     def generate(self):
         contents = [