os: improve Android interop (#14827)

.github/workflows/ci_cross.yml

@@ -42,11 +42,6 @@ jobs:
           ./v -os windows cmd/v
           ./v -os windows examples/2048/2048.v
 
-      - name: Compile to raw Android (non-graphic) compatible
-        run: |
-          # Test that V can compile non-graphic app to Android compatible code *without* using the -apk flag
-          ./v -os android -gc none examples/toml.v
-
   linux-cross:
     runs-on: ubuntu-20.04
     if: github.event_name != 'push' || github.event.ref == 'refs/heads/master' || github.event.repository.full_name != 'vlang/v'
@@ -64,6 +59,7 @@ jobs:
           sudo apt-get install --quiet -y libssl-dev sqlite3 libsqlite3-dev
           sudo apt-get install --quiet -y mingw-w64 wine-stable winetricks
           ## sudo apt-get install --quiet -y wine32
+
       - name: Turn off the wine crash dialog
         run: winetricks nocrashdialog
 
@@ -95,12 +91,6 @@ jobs:
           ./v -os windows examples/2048/2048.v
           ls -lart examples/2048/2048.exe
 
-      - name: toml.v can be compiled to raw Android C
-        run: |
-          # Test that V can compile non-graphic app to Android compatible code *without* using the -apk flag
-          ./v -os android -gc none examples/toml.v
-
-
   windows-cross:
     runs-on: windows-2019
     if: github.event_name != 'push' || github.event.ref == 'refs/heads/master' || github.event.repository.full_name != 'vlang/v'

vlib/os/os_android.c.v

@@ -1,41 +1,104 @@
 module os
 
-struct C.AAsset {
+pub enum AssetMode {
+	buffer = C.AASSET_MODE_BUFFER // Caller plans to ask for a read-only buffer with all data.
+	random = C.AASSET_MODE_RANDOM // Read chunks, and seek forward and backward.
+	streaming = C.AASSET_MODE_STREAMING // Read sequentially, with an occasional forward seek.
+	unknown = C.AASSET_MODE_UNKNOWN // No specific information about how data will be accessed.
 }
 
+struct C.ANativeActivity {
+	assetManager     &AssetManager // Pointer to the Asset Manager instance for the application.
+	clazz            voidptr       // (jobject) The NativeActivity object handle.
+	env              voidptr       // (JNIEnv *) JNI context for the main thread of the app.
+	externalDataPath &char   // Path to this application's external (removable/mountable) data directory.
+	instance         voidptr // This is the native instance of the application.
+	internalDataPath &char   // Path to this application's internal data directory.
+	obbPath          &char   // Available starting with Honeycomb: path to the directory containing the application's OBB files (if any).
+	sdkVersion       int     // The platform's SDK version code.
+	vm               voidptr // (JavaVM *) The global handle on the process's Java VM.
+}
+
+// NativeActivity defines the native side of an android.app.NativeActivity.
+pub type NativeActivity = C.ANativeActivity
+
 struct C.AAssetManager {
 }
 
-struct C.ANativeActivity {
-	assetManager voidptr
-}
+// AssetManager provides access to an application's raw assets by creating Asset objects.
+pub type AssetManager = C.AAssetManager
 
 fn C.AAssetManager_open(&C.AAssetManager, &char, int) &C.AAsset
 
+// open opens an Android `Asset`
+pub fn (am &AssetManager) open(filename string, mode AssetMode) !&Asset {
+	asset := C.AAssetManager_open(am, filename.str, int(mode))
+	if isnil(asset) {
+		return error('file `$filename` not found')
+	}
+	return asset
+}
+
+struct C.AAsset {
+}
+
+pub type Asset = C.AAsset
+
+fn C.AAsset_getBuffer(&C.AAsset) voidptr
+
+// get_buffer returns a pointer to a buffer holding the entire contents of the asset.
+pub fn (a &Asset) get_buffer() voidptr {
+	return C.AAsset_getBuffer(a)
+}
+
 fn C.AAsset_getLength(&C.AAsset) int
 
-fn C.AAsset_read(&C.AAsset, voidptr, int) int
+// get_length returns the total size of the asset data.
+pub fn (a &Asset) get_length() int {
+	return C.AAsset_getLength(a)
+}
+
+fn C.AAsset_getLength64(&C.AAsset) i64
+
+// get_length_64 returns the total size of the asset data.
+// get_length_64 returns  the size using a 64-bit number insted of 32-bit as `get_length`.
+pub fn (a &Asset) get_length_64() i64 {
+	return C.AAsset_getLength64(a)
+}
+
+fn C.AAsset_read(&C.AAsset, voidptr, usize) int
+
+// read attempts to read 'count' bytes of data from the current offset.
+// read returns the number of bytes read, zero on EOF, or < 0 on error.
+pub fn (a &Asset) read(buffer voidptr, count usize) int {
+	return C.AAsset_read(a, buffer, count)
+}
 
 fn C.AAsset_close(&C.AAsset)
 
-pub fn read_apk_asset(file string) ?[]u8 {
+// close closes the asset, freeing all associated resources.
+pub fn (a &Asset) close() {
+	C.AAsset_close(a)
+}
+
+// read_apk_asset returns all the data located at `path`.
+// `path` is expected to be relative to the `assets`
+pub fn read_apk_asset(path string) ![]u8 {
 	$if apk {
-		act := &C.ANativeActivity(C.sapp_android_get_native_activity())
+		act := &NativeActivity(C.sapp_android_get_native_activity())
 		if isnil(act) {
-			return error('Could not get reference to Android activity')
+			return error('could not get reference to Android activity')
 		}
-		asset := C.AAssetManager_open(&C.AAssetManager(act.assetManager), file.str, C.AASSET_MODE_STREAMING)
-		if isnil(asset) {
-			return error('File `$file` not found')
-		}
-		len := C.AAsset_getLength(asset)
+		asset_manager := &AssetManager(act.assetManager)
+		asset := asset_manager.open(path, .streaming)!
+		len := asset.get_length()
 		buf := []u8{len: len}
 		for {
-			if C.AAsset_read(asset, buf.data, len) > 0 {
+			if asset.read(buf.data, usize(len)) > 0 {
 				break
 			}
 		}
-		C.AAsset_close(asset)
+		asset.close()
 		return buf
 	} $else {
 		return error(@FN + ' can only be used with APK/AAB packaged Android apps')