Read/write scenarios in JSON, so people can manipulate them in any language. #313

abstutil/src/io.rs

@@ -156,6 +156,14 @@ pub fn read_binary<T: DeserializeOwned>(path: String, timer: &mut Timer) -> T {
     }
 }
 
+pub fn read_object<T: DeserializeOwned>(path: String, timer: &mut Timer) -> Result<T, Error> {
+    if path.ends_with(".bin") {
+        maybe_read_binary(path, timer)
+    } else {
+        maybe_read_json(path, timer)
+    }
+}
+
 // For BTreeMaps with struct keys. See https://github.com/serde-rs/json/issues/402.
 
 pub fn serialize_btreemap<S: Serializer, K: Serialize, V: Serialize>(
@@ -438,13 +446,13 @@ pub fn basename(path: &str) -> String {
 }
 
 #[cfg(not(target_arch = "wasm32"))]
-pub fn file_exists(path: String) -> bool {
-    Path::new(&path).exists()
+pub fn file_exists<I: Into<String>>(path: I) -> bool {
+    Path::new(&path.into()).exists()
 }
 
 #[cfg(target_arch = "wasm32")]
-pub fn file_exists(path: String) -> bool {
+pub fn file_exists<I: Into<String>>(path: I) -> bool {
     SYSTEM_DATA
-        .get_file(path.trim_start_matches("../data/system/"))
+        .get_file(path.into().trim_start_matches("../data/system/"))
         .is_some()
 }

abstutil/src/lib.rs

@@ -12,7 +12,7 @@ pub use crate::collections::{
 pub use crate::io::{
     basename, deserialize_btreemap, deserialize_multimap, deserialize_usize, file_exists,
     find_next_file, find_prev_file, from_json, list_all_objects, list_dir, load_all_objects,
-    maybe_read_binary, maybe_read_json, read_binary, read_json, serialize_btreemap,
+    maybe_read_binary, maybe_read_json, read_binary, read_json, read_object, serialize_btreemap,
     serialize_multimap, serialize_usize, serialized_size_bytes, slurp_file, to_json, write_binary,
     write_json, FileWithProgress,
 };
@@ -119,9 +119,17 @@ pub fn path_prebaked_results(map_name: &str, scenario_name: &str) -> String {
 }
 
 pub fn path_scenario(map_name: &str, scenario_name: &str) -> String {
-    path(format!(
+    // TODO Getting complicated. Looks for .bin, then .json.
+    let p = path(format!(
         "system/scenarios/{}/{}.bin",
         map_name, scenario_name
+    ));
+    if file_exists(&p) {
+        return p;
+    }
+    path(format!(
+        "system/scenarios/{}/{}.json",
+        map_name, scenario_name
     ))
 }
 pub fn path_all_scenarios(map_name: &str) -> String {

abstutil/src/time.rs

@@ -652,6 +652,7 @@ impl<'a> Read for Timer<'a> {
                 prettyprint_usize(file.total_bytes / 1024 / 1024),
                 prettyprint_time(elapsed)
             );
+            if self.outermost_name != "throwaway" {
                 if file.last_printed_at.is_none() {
                     self.println(line.clone());
                 } else {
@@ -661,11 +662,13 @@ impl<'a> Read for Timer<'a> {
                         sink.reprintln(line.clone());
                     }
                 }
+            }
             self.stack.pop();
             self.add_result(elapsed, line);
         } else if file.last_printed_at.is_none()
             || elapsed_seconds(file.last_printed_at.unwrap()) >= PROGRESS_FREQUENCY_SECONDS
         {
+            if self.outermost_name != "throwaway" {
                 let line = format!(
                     "Reading {}: {}/{} MB... {}",
                     file.path,
@@ -685,6 +688,7 @@ impl<'a> Read for Timer<'a> {
                         sink.reprintln(line);
                     }
                 }
+            }
 
             file.last_printed_at = Some(Instant::now());
         }

book/src/dev/README.md

@@ -154,7 +154,8 @@ problems is useful. It's also fine to crash when initially constructing all of
 the renderable map objects, because this crash will consistently happen at
 startup-time and be noticed by somebody developing before a player gets to it.
 
-Regarding Testing: You'll surely note the lack of unit tests. If it bothers you, let's talk about
-what tests should exist. In the meantime, note lots of validation does happen
-via importing maps, running the prebaked scenarios, and screenshot diffing.
-Please read more in depth in the [testing strategy](https://dabreegster.github.io/abstreet/dev/testing.html) doc.
+Regarding Testing: You'll surely note the lack of unit tests. If it bothers you,
+let's talk about what tests should exist. In the meantime, note lots of
+validation does happen via importing maps, running the prebaked scenarios, and
+screenshot diffing. Please read more in depth in the
+[testing strategy](https://dabreegster.github.io/abstreet/dev/testing.html) doc.

book/src/dev/api.md

@@ -51,18 +51,38 @@ are missing, etc. A summary of the commands available so far:
     normally. You can also later run the `headless` server with
     `--edits=name_of_edits`.
 
-## Related tools
-
-There's no API to create trips. Instead, you can
-[import trips from your own data](https://dabreegster.github.io/abstreet/trafficsim/travel_demand.html#custom-import).
+## Working with the map model
 
 If you need to deeply inspect the map, you can dump it to JSON:
 
 ```
-cargo run --bin dump_map data/system/maps/montlake.bin
+cargo run --bin dump_map data/system/maps/montlake.bin > montlake.json
 ```
 
 The format of the map isn't well-documented yet. See the
 [generated API docs](https://dabreegster.github.io/abstreet/rustdoc/map_model/index.html)
 and [the map model docs](https://dabreegster.github.io/abstreet/map/index.html)
 in the meantime.
+
+## Creating trips
+
+There's no API yet to create trips. Instead, you can
+[import trips from your own data](https://dabreegster.github.io/abstreet/trafficsim/travel_demand.html#custom-import).
+
+You can also dump Scenarios (the file that defines all of the people and trips)
+to JSON:
+
+```
+cargo run --bin dump_scenario data/system/scenarios/montlake/weekday.bin > montlake_weekday.json
+```
+
+You can modify the JSON, then put the file back in the appropriate directory and
+use it in-game:
+
+```
+cargo run --bin game data/system/scenarios/montlake/modified_scenario.json
+```
+
+The Scenario format is also undocumented, but see the
+[generated API docs](https://dabreegster.github.io/abstreet/rustdoc/sim/struct.Scenario.html)
+anyway.

game/src/sandbox/gameplay/mod.rs

@@ -117,7 +117,7 @@ impl GameplayMode {
             ScenarioGenerator::proletariat_robot(map, &mut rng, timer)
         } else {
             let path = abstutil::path_scenario(map.get_name(), &name);
-            let mut scenario = match abstutil::maybe_read_binary(path.clone(), timer) {
+            let mut scenario = match abstutil::read_object(path.clone(), timer) {
                 Ok(s) => s,
                 Err(err) => {
                     Map::corrupt_err(path, err);

importer/src/bin/dump_scenario.rs

@@ -0,0 +1,9 @@
+use abstutil::{CmdArgs, Timer};
+use sim::Scenario;
+
+fn main() {
+    let mut args = CmdArgs::new();
+    let scenario: Scenario = abstutil::read_binary(args.required_free(), &mut Timer::throwaway());
+    println!("{}", abstutil::to_json(&scenario));
+    args.done();
+}