apk: Embed configurable assets in asset/ directory

Android apps might want to ship with extra files - assets - to
complement the native build.  These could be single files or folders
that are included recursively.  the `file_name()` of the given path is
added directly to the `assets/` directory, and any directory structure
beyond that point is maintained.

Assets are specified in the following way in `manifest.yaml`:

    android:
      assets:
        - some/path
        - { path: some/path } # Same as above
        - { path: some/path, optional: true } # Do not error if this  path doesn't exist
        - { path: some/path, alignment: 4096 } # Page-aligned for optimal use with AASSET_MODE_BUFFER and AAsset_getBuffer
        - { path: some/path, alignment: unaligned }
        - { path: some/path, alignment: compressed }

apk/src/lib.rs

@@ -3,7 +3,7 @@ use crate::res::Chunk;
 use anyhow::{Context, Result};
 use std::io::Cursor;
 use std::path::{Path, PathBuf};
-use xcommon::{Scaler, ScalerOpts, Zip, ZipFile, ZipFileOptions};
+use xcommon::{Scaler, ScalerOpts, Zip, ZipFileOptions};
 
 mod compiler;
 pub mod manifest;
@@ -77,16 +77,27 @@ impl Apk {
         Ok(())
     }
 
+    pub fn add_asset(&mut self, asset: &Path, opts: ZipFileOptions) -> Result<()> {
+        let file_name = asset
+            .file_name()
+            .context("Asset must have file_name component")?;
+        let dest = Path::new("assets").join(file_name);
+        if asset.is_dir() {
+            tracing::info!("Embedding asset directory `{}`", asset.display());
+            self.zip.add_directory(asset, &dest, opts)
+        } else {
+            tracing::info!("Embedding asset file `{}`", asset.display());
+            self.zip.add_file(asset, &dest, opts)
+        }
+        .with_context(|| format!("While embedding asset `{}`", asset.display()))
+    }
+
     pub fn add_dex(&mut self, dex: &Path) -> Result<()> {
         self.zip
             .add_file(dex, Path::new("classes.dex"), ZipFileOptions::Compressed)?;
         Ok(())
     }
 
-    pub fn add_zip_file(&mut self, f: ZipFile) -> Result<()> {
-        self.zip.add_zip_file(f)
-    }
-
     pub fn add_lib(&mut self, target: Target, path: &Path) -> Result<()> {
         let name = path
             .file_name()
@@ -100,14 +111,6 @@ impl Apk {
         )
     }
 
-    pub fn add_file(&mut self, source: &Path, dest: &Path, opts: ZipFileOptions) -> Result<()> {
-        self.zip.add_file(source, dest, opts)
-    }
-
-    pub fn add_directory(&mut self, source: &Path, dest: &Path) -> Result<()> {
-        self.zip.add_directory(source, dest)
-    }
-
     pub fn finish(self, signer: Option<Signer>) -> Result<()> {
         self.zip.finish()?;
         crate::sign::sign(&self.path, signer)?;

msix/src/lib.rs

@@ -73,8 +73,13 @@ impl Msix {
         self.zip.add_file(source, dest, opts)
     }
 
-    pub fn add_directory(&mut self, source: &Path, dest: &Path) -> Result<()> {
-        self.zip.add_directory(source, dest)
+    pub fn add_directory(
+        &mut self,
+        source: &Path,
+        dest: &Path,
+        opts: ZipFileOptions,
+    ) -> Result<()> {
+        self.zip.add_directory(source, dest, opts)
     }
 
     pub fn finish(mut self, signer: Option<Signer>) -> Result<()> {

xbuild/src/command/build.rs

@@ -83,6 +83,14 @@ pub fn build(env: &BuildEnv) -> Result<()> {
                 )?;
                 apk.add_res(env.icon(), &env.android_jar())?;
 
+                for asset in &env.config().android().assets {
+                    let path = env.cargo().package_root().join(asset.path());
+
+                    if !asset.optional() || path.exists() {
+                        apk.add_asset(&path, asset.alignment().to_zip_file_options())?
+                    }
+                }
+
                 if has_lib {
                     for target in env.target().compile_targets() {
                         let arch_dir = platform_dir.join(target.arch().to_string());
@@ -256,6 +264,7 @@ pub fn build(env: &BuildEnv) -> Result<()> {
                 ipa.add_directory(
                     &app,
                     &Path::new("Payload").join(format!("{}.app", env.name())),
+                    ZipFileOptions::Compressed,
                 )?;
                 ipa.finish()?;
             }

xbuild/src/config.rs

@@ -7,6 +7,7 @@ use appbundle::InfoPlist;
 use msix::AppxManifest;
 use serde::Deserialize;
 use std::path::{Path, PathBuf};
+use xcommon::ZipFileOptions;
 
 #[derive(Clone, Debug, Default)]
 pub struct Config {
@@ -312,7 +313,84 @@ impl Config {
     }
 }
 
+#[derive(Clone, Copy, Debug, Default, Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum UnalignedCompressed {
+    /// Don't align this file
+    Unaligned,
+    /// Compressed files do not need to be aligned, as they have to be unpacked and decompressed anyway
+    #[default]
+    Compressed,
+}
+
+#[derive(Clone, Copy, Debug, Deserialize)]
+#[serde(untagged)]
+pub enum ZipAlignmentOptions {
+    /// Align this file to the given number of bytes
+    Aligned(u16),
+    /// Used to wrap a tagged enum with an untagged alignment value
+    UnalignedCompressed(UnalignedCompressed),
+}
+
+impl Default for ZipAlignmentOptions {
+    fn default() -> Self {
+        Self::UnalignedCompressed(UnalignedCompressed::Compressed)
+    }
+}
+
+impl ZipAlignmentOptions {
+    pub fn to_zip_file_options(self) -> ZipFileOptions {
+        match self {
+            Self::Aligned(a) => ZipFileOptions::Aligned(a),
+            Self::UnalignedCompressed(UnalignedCompressed::Unaligned) => ZipFileOptions::Unaligned,
+            Self::UnalignedCompressed(UnalignedCompressed::Compressed) => {
+                ZipFileOptions::Compressed
+            }
+        }
+    }
+}
+
+#[derive(Clone, Debug, Deserialize)]
+#[serde(untagged, deny_unknown_fields)]
+pub enum AssetPath {
+    Path(PathBuf),
+    Extended {
+        path: PathBuf,
+        #[serde(default)]
+        optional: bool,
+        #[serde(default)]
+        alignment: ZipAlignmentOptions,
+    },
+}
+
+impl AssetPath {
+    #[inline]
+    pub fn path(&self) -> &Path {
+        match self {
+            AssetPath::Path(path) => path,
+            AssetPath::Extended { path, .. } => path,
+        }
+    }
+
+    #[inline]
+    pub fn optional(&self) -> bool {
+        match self {
+            AssetPath::Path(_) => false,
+            AssetPath::Extended { optional, .. } => *optional,
+        }
+    }
+
+    #[inline]
+    pub fn alignment(&self) -> ZipAlignmentOptions {
+        match self {
+            AssetPath::Path(_) => Default::default(),
+            AssetPath::Extended { alignment, .. } => *alignment,
+        }
+    }
+}
+
 #[derive(Deserialize)]
+#[serde(deny_unknown_fields)]
 struct RawConfig {
     #[serde(flatten)]
     generic: Option<GenericConfig>,
@@ -324,13 +402,15 @@ struct RawConfig {
 }
 
 #[derive(Clone, Debug, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct GenericConfig {
     icon: Option<PathBuf>,
     #[serde(default)]
     runtime_libs: Vec<PathBuf>,
 }
 
 #[derive(Clone, Debug, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct AndroidConfig {
     #[serde(flatten)]
     generic: GenericConfig,
@@ -342,9 +422,12 @@ pub struct AndroidConfig {
     pub gradle: bool,
     #[serde(default)]
     pub wry: bool,
+    #[serde(default)]
+    pub assets: Vec<AssetPath>,
 }
 
 #[derive(Clone, Debug, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct IosConfig {
     #[serde(flatten)]
     generic: GenericConfig,
@@ -353,19 +436,22 @@ pub struct IosConfig {
 }
 
 #[derive(Clone, Debug, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct MacosConfig {
     #[serde(flatten)]
     generic: GenericConfig,
     pub info: InfoPlist,
 }
 
 #[derive(Clone, Debug, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct LinuxConfig {
     #[serde(flatten)]
     generic: GenericConfig,
 }
 
 #[derive(Clone, Debug, Default, Deserialize)]
+#[serde(deny_unknown_fields)]
 pub struct WindowsConfig {
     #[serde(flatten)]
     generic: GenericConfig,

xcommon/src/lib.rs

@@ -286,14 +286,20 @@ impl Zip {
     }
 
     pub fn add_file(&mut self, source: &Path, dest: &Path, opts: ZipFileOptions) -> Result<()> {
-        let mut f = File::open(source)?;
+        let mut f = File::open(source)
+            .with_context(|| format!("While opening file `{}`", source.display()))?;
         self.start_file(dest, opts)?;
         std::io::copy(&mut f, &mut self.zip)?;
         Ok(())
     }
 
-    pub fn add_directory(&mut self, source: &Path, dest: &Path) -> Result<()> {
-        add_recursive(self, source, dest)?;
+    pub fn add_directory(
+        &mut self,
+        source: &Path,
+        dest: &Path,
+        opts: ZipFileOptions,
+    ) -> Result<()> {
+        add_recursive(self, source, dest, opts)?;
         Ok(())
     }
 
@@ -335,17 +341,19 @@ impl Zip {
     }
 }
 
-fn add_recursive(zip: &mut Zip, source: &Path, dest: &Path) -> Result<()> {
-    for entry in std::fs::read_dir(source)? {
+fn add_recursive(zip: &mut Zip, source: &Path, dest: &Path, opts: ZipFileOptions) -> Result<()> {
+    for entry in std::fs::read_dir(source)
+        .with_context(|| format!("While reading directory `{}`", source.display()))?
+    {
         let entry = entry?;
         let file_name = entry.file_name();
         let source = source.join(&file_name);
         let dest = dest.join(&file_name);
         let file_type = entry.file_type()?;
         if file_type.is_dir() {
-            add_recursive(zip, &source, &dest)?;
+            add_recursive(zip, &source, &dest, opts)?;
         } else if file_type.is_file() {
-            zip.add_file(&source, &dest, ZipFileOptions::Compressed)?;
+            zip.add_file(&source, &dest, opts)?;
         }
     }
     Ok(())