aconfig: add create-device-config-defaults command

DeviceConfig is the backend for READ_WRITE flags.

Add a new command "create-device-config-defaults" to create a file that
DeviceConfig will read to pre-populate its data store on first init.

This will be used to quickly switch flag values during CI tests:
rebuilding and reflashing a device would have the same effect, but would
be costlier. This feature is not expected to be used outside CI tests.

Note: because DeviceConfig only works with READ_WRITE flags, the
generated file excludes READ_ONLY flags.

Bug: 285468565
Test: atest aconfig.test
Change-Id: I4caff1a10647b8da0ce4e3615678993a957a92dd

tools/aconfig/src/commands.rs

@@ -22,8 +22,8 @@ use std::fmt;
 use std::io::Read;
 use std::path::PathBuf;
 
-use crate::aconfig::{FlagDeclarations, FlagValue};
-use crate::cache::{Cache, CacheBuilder};
+use crate::aconfig::{FlagDeclarations, FlagState, FlagValue, Permission};
+use crate::cache::{Cache, CacheBuilder, Item};
 use crate::codegen_cpp::generate_cpp_code;
 use crate::codegen_java::generate_java_code;
 use crate::codegen_rust::generate_rust_code;
@@ -105,6 +105,24 @@ pub fn create_rust_lib(cache: Cache) -> Result<OutputFile> {
     generate_rust_code(&cache)
 }
 
+pub fn create_device_config_defaults(caches: Vec<Cache>) -> Result<Vec<u8>> {
+    let mut output = Vec::new();
+    for item in sort_and_iter_items(caches).filter(|item| item.permission == Permission::ReadWrite)
+    {
+        let line = format!(
+            "{}/{}:{}\n",
+            item.namespace,
+            item.name,
+            match item.state {
+                FlagState::Enabled => "enabled",
+                FlagState::Disabled => "disabled",
+            }
+        );
+        output.extend_from_slice(line.as_bytes());
+    }
+    Ok(output)
+}
+
 #[derive(Copy, Clone, Debug, PartialEq, Eq, ValueEnum)]
 pub enum DumpFormat {
     Text,
@@ -112,29 +130,26 @@ pub enum DumpFormat {
     Protobuf,
 }
 
-pub fn dump_cache(mut caches: Vec<Cache>, format: DumpFormat) -> Result<Vec<u8>> {
+pub fn dump_cache(caches: Vec<Cache>, format: DumpFormat) -> Result<Vec<u8>> {
     let mut output = Vec::new();
-    caches.sort_by_cached_key(|cache| cache.namespace().to_string());
-    for cache in caches.into_iter() {
-        match format {
-            DumpFormat::Text => {
-                let mut lines = vec![];
-                for item in cache.iter() {
-                    lines.push(format!(
-                        "{}/{}: {:?} {:?}\n",
-                        item.namespace, item.name, item.state, item.permission
-                    ));
-                }
-                output.append(&mut lines.concat().into());
+    match format {
+        DumpFormat::Text => {
+            for item in sort_and_iter_items(caches) {
+                let line = format!(
+                    "{}/{}: {:?} {:?}\n",
+                    item.namespace, item.name, item.state, item.permission
+                );
+                output.extend_from_slice(line.as_bytes());
             }
-            DumpFormat::Debug => {
-                let mut lines = vec![];
-                for item in cache.iter() {
-                    lines.push(format!("{:#?}\n", item));
-                }
-                output.append(&mut lines.concat().into());
+        }
+        DumpFormat::Debug => {
+            for item in sort_and_iter_items(caches) {
+                let line = format!("{:#?}\n", item);
+                output.extend_from_slice(line.as_bytes());
             }
-            DumpFormat::Protobuf => {
+        }
+        DumpFormat::Protobuf => {
+            for cache in sort_and_iter_caches(caches) {
                 let parsed_flags: ProtoParsedFlags = cache.into();
                 parsed_flags.write_to_vec(&mut output)?;
             }
@@ -143,6 +158,15 @@ pub fn dump_cache(mut caches: Vec<Cache>, format: DumpFormat) -> Result<Vec<u8>>
     Ok(output)
 }
 
+fn sort_and_iter_items(caches: Vec<Cache>) -> impl Iterator<Item = Item> {
+    sort_and_iter_caches(caches).flat_map(|cache| cache.into_iter())
+}
+
+fn sort_and_iter_caches(mut caches: Vec<Cache>) -> impl Iterator<Item = Cache> {
+    caches.sort_by_cached_key(|cache| cache.namespace().to_string());
+    caches.into_iter()
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -202,6 +226,14 @@ mod tests {
         assert_eq!(Permission::ReadOnly, item.permission);
     }
 
+    #[test]
+    fn test_create_device_config_defaults() {
+        let caches = vec![crate::test::create_cache()];
+        let bytes = create_device_config_defaults(caches).unwrap();
+        let text = std::str::from_utf8(&bytes).unwrap();
+        assert_eq!("test/disabled_rw:disabled\ntest/enabled_rw:enabled\n", text);
+    }
+
     #[test]
     fn test_dump_text_format() {
         let caches = vec![create_test_cache_ns1()];

tools/aconfig/src/main.rs

@@ -64,6 +64,11 @@ fn cli() -> Command {
                 .arg(Arg::new("cache").long("cache").required(true))
                 .arg(Arg::new("out").long("out").required(true)),
         )
+        .subcommand(
+            Command::new("create-device-config-defaults")
+                .arg(Arg::new("cache").long("cache").action(ArgAction::Append).required(true))
+                .arg(Arg::new("out").long("out").default_value("-")),
+        )
         .subcommand(
             Command::new("dump")
                 .arg(Arg::new("cache").long("cache").action(ArgAction::Append).required(true))
@@ -111,6 +116,15 @@ fn write_output_file_realtive_to_dir(root: &Path, output_file: &OutputFile) -> R
     Ok(())
 }
 
+fn write_output_to_file_or_stdout(path: &str, data: &[u8]) -> Result<()> {
+    if path == "-" {
+        io::stdout().write_all(data)?;
+    } else {
+        fs::File::create(path)?.write_all(data)?;
+    }
+    Ok(())
+}
+
 fn main() -> Result<()> {
     let matches = cli().get_matches();
     match matches.subcommand() {
@@ -147,6 +161,17 @@ fn main() -> Result<()> {
             let generated_file = commands::create_rust_lib(cache)?;
             write_output_file_realtive_to_dir(&dir, &generated_file)?;
         }
+        Some(("create-device-config-defaults", sub_matches)) => {
+            let mut caches = Vec::new();
+            for path in sub_matches.get_many::<String>("cache").unwrap_or_default() {
+                let file = fs::File::open(path)?;
+                let cache = Cache::read_from_reader(file)?;
+                caches.push(cache);
+            }
+            let output = commands::create_device_config_defaults(caches)?;
+            let path = get_required_arg::<String>(sub_matches, "out")?;
+            write_output_to_file_or_stdout(path, &output)?;
+        }
         Some(("dump", sub_matches)) => {
             let mut caches = Vec::new();
             for path in sub_matches.get_many::<String>("cache").unwrap_or_default() {
@@ -157,12 +182,7 @@ fn main() -> Result<()> {
             let format = get_required_arg::<DumpFormat>(sub_matches, "format")?;
             let output = commands::dump_cache(caches, *format)?;
             let path = get_required_arg::<String>(sub_matches, "out")?;
-            let mut file: Box<dyn Write> = if *path == "-" {
-                Box::new(io::stdout())
-            } else {
-                Box::new(fs::File::create(path)?)
-            };
-            file.write_all(&output)?;
+            write_output_to_file_or_stdout(path, &output)?;
         }
         _ => unreachable!(),
     }