aconfig: add dump protobuf format

Introduce a new protobuf format to represent the all flags parsed by
aconfig. This data in this new format is similar to that of the internal
cache object, but the protobuf is a public API for other tools to
consume and any changes to the proto spec must be backwards compatible.

When aconfig has matured more, Cache can potentially be rewritten to
work with proto structs directly, removing some of the hand-written
wrapper structs and the logic to convert to and from the proto structs.
At this point, the intermediate json format can be replaced by the
protobuf dump.

Also, teach `aconfig dump` to accept an --out <file> argument (default:
stdout).

Also, teach `aconfig dump` to read more than once cache file.

Note: the new protobuf fields refer to existing fields. It would make
sense to split the .proto file in one for input and one for output
formats, and import the common messages, but the Android build system
and cargo will need different import paths. Keep the definitions in the
same file to circumvent this problem.

Bug: 279485059
Test: atest aconfig.test
Change-Id: I55ee4a52c0fb3369d91d61406867ae03a15805c3

tools/aconfig/protos/aconfig.proto

@@ -55,3 +55,21 @@ message override {
 message override_config {
   repeated override override = 1;
 };
+
+message dump {
+  repeated dump_item item = 1;
+}
+
+message dump_trace {
+  required string source = 1;
+  required flag_state state = 2;
+  required permission permission = 3;
+}
+
+message dump_item {
+  required string id = 1;
+  required string description = 2;
+  required flag_state state = 3;
+  required permission permission = 4;
+  repeated dump_trace trace = 5;
+}

tools/aconfig/src/aconfig.rs

@@ -18,9 +18,10 @@ use anyhow::{anyhow, Context, Error, Result};
 use protobuf::{Enum, EnumOrUnknown};
 use serde::{Deserialize, Serialize};
 
+use crate::cache::{Cache, Item, TracePoint};
 use crate::protos::{
-    ProtoAndroidConfig, ProtoFlag, ProtoFlagState, ProtoOverride, ProtoOverrideConfig,
-    ProtoPermission, ProtoValue,
+    ProtoAndroidConfig, ProtoDump, ProtoDumpItem, ProtoDumpTracePoint, ProtoFlag, ProtoFlagState,
+    ProtoOverride, ProtoOverrideConfig, ProtoPermission, ProtoValue,
 };
 
 #[derive(Debug, PartialEq, Eq, Serialize, Deserialize, Clone, Copy)]
@@ -41,6 +42,15 @@ impl TryFrom<EnumOrUnknown<ProtoFlagState>> for FlagState {
     }
 }
 
+impl From<FlagState> for ProtoFlagState {
+    fn from(state: FlagState) -> Self {
+        match state {
+            FlagState::Enabled => ProtoFlagState::ENABLED,
+            FlagState::Disabled => ProtoFlagState::DISABLED,
+        }
+    }
+}
+
 #[derive(Debug, PartialEq, Eq, Serialize, Deserialize, Clone, Copy)]
 pub enum Permission {
     ReadOnly,
@@ -59,6 +69,15 @@ impl TryFrom<EnumOrUnknown<ProtoPermission>> for Permission {
     }
 }
 
+impl From<Permission> for ProtoPermission {
+    fn from(permission: Permission) -> Self {
+        match permission {
+            Permission::ReadOnly => ProtoPermission::READ_ONLY,
+            Permission::ReadWrite => ProtoPermission::READ_WRITE,
+        }
+    }
+}
+
 #[derive(Debug, PartialEq, Eq)]
 pub struct Value {
     state: FlagState,
@@ -202,6 +221,40 @@ impl TryFrom<ProtoOverride> for Override {
     }
 }
 
+impl From<Cache> for ProtoDump {
+    fn from(cache: Cache) -> Self {
+        let mut dump = ProtoDump::new();
+        for item in cache.into_iter() {
+            dump.item.push(item.into());
+        }
+        dump
+    }
+}
+
+impl From<Item> for ProtoDumpItem {
+    fn from(item: Item) -> Self {
+        let mut dump_item = crate::protos::ProtoDumpItem::new();
+        dump_item.set_id(item.id.clone());
+        dump_item.set_description(item.description.clone());
+        dump_item.set_state(item.state.into());
+        dump_item.set_permission(item.permission.into());
+        for trace in item.trace.into_iter() {
+            dump_item.trace.push(trace.into());
+        }
+        dump_item
+    }
+}
+
+impl From<TracePoint> for ProtoDumpTracePoint {
+    fn from(tracepoint: TracePoint) -> Self {
+        let mut dump_tracepoint = ProtoDumpTracePoint::new();
+        dump_tracepoint.set_source(format!("{}", tracepoint.source));
+        dump_tracepoint.set_state(tracepoint.state.into());
+        dump_tracepoint.set_permission(tracepoint.permission.into());
+        dump_tracepoint
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;

tools/aconfig/src/cache.rs

@@ -92,9 +92,11 @@ impl Cache {
     pub fn iter(&self) -> impl Iterator<Item = &Item> {
         self.items.iter()
     }
-}
 
-impl Item {}
+    pub fn into_iter(self) -> impl Iterator<Item = Item> {
+        self.items.into_iter()
+    }
+}
 
 #[cfg(test)]
 mod tests {

tools/aconfig/src/commands.rs

@@ -16,12 +16,14 @@
 
 use anyhow::{Context, Result};
 use clap::ValueEnum;
+use protobuf::Message;
 use serde::{Deserialize, Serialize};
 use std::fmt;
 use std::io::Read;
 
 use crate::aconfig::{Flag, Override};
 use crate::cache::Cache;
+use crate::protos::ProtoDump;
 
 #[derive(Serialize, Deserialize, Clone, Debug)]
 pub enum Source {
@@ -74,22 +76,32 @@ pub fn create_cache(build_id: u32, aconfigs: Vec<Input>, overrides: Vec<Input>)
 pub enum Format {
     Text,
     Debug,
+    Protobuf,
 }
 
-pub fn dump_cache(cache: Cache, format: Format) -> Result<()> {
+pub fn dump_cache(cache: Cache, format: Format) -> Result<Vec<u8>> {
     match format {
         Format::Text => {
+            let mut lines = vec![];
             for item in cache.iter() {
-                println!("{}: {:?}", item.id, item.state);
+                lines.push(format!("{}: {:?}\n", item.id, item.state));
             }
+            Ok(lines.concat().into())
         }
         Format::Debug => {
+            let mut lines = vec![];
             for item in cache.iter() {
-                println!("{:?}", item);
+                lines.push(format!("{:?}\n", item));
             }
+            Ok(lines.concat().into())
+        }
+        Format::Protobuf => {
+            let dump: ProtoDump = cache.into();
+            let mut output = vec![];
+            dump.write_to_vec(&mut output)?;
+            Ok(output)
         }
     }
-    Ok(())
 }
 
 #[cfg(test)]
@@ -97,8 +109,7 @@ mod tests {
     use super::*;
     use crate::aconfig::{FlagState, Permission};
 
-    #[test]
-    fn test_create_cache() {
+    fn create_test_cache() -> Cache {
         let s = r#"
         flag {
             id: "a"
@@ -108,6 +119,14 @@ mod tests {
                 permission: READ_WRITE
             }
         }
+        flag {
+            id: "b"
+            description: "Description of b"
+            value {
+                state: ENABLED
+                permission: READ_ONLY
+            }
+        }
         "#;
         let aconfigs = vec![Input { source: Source::Memory, reader: Box::new(s.as_bytes()) }];
         let o = r#"
@@ -118,9 +137,36 @@ mod tests {
         }
         "#;
         let overrides = vec![Input { source: Source::Memory, reader: Box::new(o.as_bytes()) }];
-        let cache = create_cache(1, aconfigs, overrides).unwrap();
+        create_cache(1, aconfigs, overrides).unwrap()
+    }
+
+    #[test]
+    fn test_create_cache() {
+        let cache = create_test_cache(); // calls create_cache
         let item = cache.iter().find(|&item| item.id == "a").unwrap();
         assert_eq!(FlagState::Disabled, item.state);
         assert_eq!(Permission::ReadOnly, item.permission);
     }
+
+    #[test]
+    fn test_dump_text_format() {
+        let cache = create_test_cache();
+        let bytes = dump_cache(cache, Format::Text).unwrap();
+        let text = std::str::from_utf8(&bytes).unwrap();
+        assert!(text.contains("a: Disabled"));
+    }
+
+    #[test]
+    fn test_dump_protobuf_format() {
+        use protobuf::Message;
+
+        let cache = create_test_cache();
+        let bytes = dump_cache(cache, Format::Protobuf).unwrap();
+        let actual = ProtoDump::parse_from_bytes(&bytes).unwrap();
+
+        assert_eq!(
+            vec!["a".to_string(), "b".to_string()],
+            actual.item.iter().map(|item| item.id.clone().unwrap()).collect::<Vec<_>>()
+        );
+    }
 }

tools/aconfig/src/main.rs

@@ -19,6 +19,8 @@
 use anyhow::Result;
 use clap::{builder::ArgAction, builder::EnumValueParser, Arg, ArgMatches, Command};
 use std::fs;
+use std::io;
+use std::io::Write;
 
 mod aconfig;
 mod cache;
@@ -44,12 +46,15 @@ fn cli() -> Command {
                 .arg(Arg::new("cache").long("cache").required(true)),
         )
         .subcommand(
-            Command::new("dump").arg(Arg::new("cache").long("cache").required(true)).arg(
-                Arg::new("format")
-                    .long("format")
-                    .value_parser(EnumValueParser::<commands::Format>::new())
-                    .default_value("text"),
-            ),
+            Command::new("dump")
+                .arg(Arg::new("cache").long("cache").required(true))
+                .arg(
+                    Arg::new("format")
+                        .long("format")
+                        .value_parser(EnumValueParser::<commands::Format>::new())
+                        .default_value("text"),
+                )
+                .arg(Arg::new("out").long("out").default_value("-")),
         )
 }
 
@@ -79,7 +84,14 @@ fn main() -> Result<()> {
             let file = fs::File::open(path)?;
             let cache = Cache::read_from_reader(file)?;
             let format = sub_matches.get_one("format").unwrap();
-            commands::dump_cache(cache, *format)?;
+            let output = commands::dump_cache(cache, *format)?;
+            let path = sub_matches.get_one::<String>("out").unwrap();
+            let mut file: Box<dyn Write> = if path == "-" {
+                Box::new(io::stdout())
+            } else {
+                Box::new(fs::File::create(path)?)
+            };
+            file.write_all(&output)?;
         }
         _ => unreachable!(),
     }

tools/aconfig/src/protos.rs

@@ -48,6 +48,15 @@ pub use aconfig_protos::aconfig::Permission as ProtoPermission;
 #[cfg(not(feature = "cargo"))]
 pub use aconfig_protos::aconfig::Flag_state as ProtoFlagState;
 
+#[cfg(not(feature = "cargo"))]
+pub use aconfig_protos::aconfig::Dump as ProtoDump;
+
+#[cfg(not(feature = "cargo"))]
+pub use aconfig_protos::aconfig::Dump_item as ProtoDumpItem;
+
+#[cfg(not(feature = "cargo"))]
+pub use aconfig_protos::aconfig::Dump_trace as ProtoDumpTracePoint;
+
 // ---- When building with cargo ----
 #[cfg(feature = "cargo")]
 include!(concat!(env!("OUT_DIR"), "/aconfig_proto/mod.rs"));
@@ -73,6 +82,15 @@ pub use aconfig::Permission as ProtoPermission;
 #[cfg(feature = "cargo")]
 pub use aconfig::Flag_state as ProtoFlagState;
 
+#[cfg(feature = "cargo")]
+pub use aconfig::Dump as ProtoDump;
+
+#[cfg(feature = "cargo")]
+pub use aconfig::Dump_item as ProtoDumpItem;
+
+#[cfg(feature = "cargo")]
+pub use aconfig::Dump_trace as ProtoDumpTracePoint;
+
 // ---- Common for both the Android tool-chain and cargo ----
 use anyhow::Result;