ixa/
global_properties.rs

1//! A generic mechanism for storing context-wide data.
2//!
3//! Global properties are not mutable and represent variables that are
4//! required in a global scope during the simulation, such as
5//! simulation parameters.
6//! A global property can be of any type and is just a value
7//! stored in the context. Global properties are defined by the
8//! [`crate::define_global_property!()`] macro and can then be
9//! set in one of two ways:
10//!
11//! * Directly by using [`Context::set_global_property_value()`]
12//! * Loaded from a configuration file using [`Context::load_global_properties()`]
13//!
14//! Attempting to change a global property which has been set already
15//! will result in an error.
16//!
17//! Global properties can be read with [`Context::get_global_property_value()`]
18use std::any::Any;
19use std::cell::RefCell;
20use std::error::Error;
21use std::fmt::Debug;
22use std::fs;
23use std::io::BufReader;
24use std::path::Path;
25use std::sync::atomic::{AtomicUsize, Ordering};
26use std::sync::{Arc, LazyLock, Mutex};
27
28use serde::de::DeserializeOwned;
29
30use crate::context::Context;
31use crate::error::IxaError;
32use crate::{trace, ContextBase, HashMap, HashMapExt};
33
34type PropertySetterFn =
35    dyn Fn(&mut Context, &str, serde_json::Value) -> Result<(), IxaError> + Send + Sync;
36
37// This is a global list of all the global properties that
38// are compiled in. Fundamentally it's a HashMap of property
39// names to the setter function, but it's wrapped in the
40// RefCell/Mutex/LazyLock combo to allow it to be globally
41// shared and initialized at startup time while still being
42// safe.
43#[doc(hidden)]
44#[allow(clippy::type_complexity)]
45pub static GLOBAL_PROPERTIES: LazyLock<Mutex<RefCell<HashMap<String, Arc<PropertySetterFn>>>>> =
46    LazyLock::new(|| Mutex::new(RefCell::new(HashMap::new())));
47
48/// Global property ID counter, keeps track of the ID that will be assigned to
49/// the next global property that requests an ID.
50static NEXT_GLOBAL_PROPERTY_ID: Mutex<usize> = Mutex::new(0);
51
52/// A convenience getter for `NEXT_GLOBAL_PROPERTY_ID`.
53#[must_use]
54pub fn get_global_property_count() -> usize {
55    *NEXT_GLOBAL_PROPERTY_ID.lock().unwrap()
56}
57
58/// Encapsulates the synchronization logic for initializing a global property's ID.
59///
60/// Acquires a global lock on the next available global property ID, but only
61/// increments it if we successfully initialize the provided ID. The ID of a
62/// global property is assigned at runtime but only once per type.
63#[must_use]
64pub fn initialize_global_property_id(global_property_id: &AtomicUsize) -> usize {
65    let mut guard = NEXT_GLOBAL_PROPERTY_ID.lock().unwrap();
66    let candidate = *guard;
67
68    match global_property_id.compare_exchange(
69        usize::MAX,
70        candidate,
71        Ordering::AcqRel,
72        Ordering::Acquire,
73    ) {
74        Ok(_) => {
75            *guard += 1;
76            candidate
77        }
78        Err(existing) => existing,
79    }
80}
81
82pub fn add_global_property<T: GlobalProperty>(name: &str)
83where
84    for<'de> <T as GlobalProperty>::Value: serde::Deserialize<'de>,
85{
86    trace!("Adding global property {name}");
87    let properties = GLOBAL_PROPERTIES.lock().unwrap();
88    properties
89        .borrow_mut()
90        .insert(
91            name.to_string(),
92            Arc::new(
93                |context: &mut Context, name, value| -> Result<(), IxaError> {
94                    let val: T::Value = serde_json::from_value(value)?;
95                    if context.get_global_property_value(T::new()).is_some() {
96                        return Err(IxaError::DuplicateProperty {
97                            name: name.to_string(),
98                        });
99                    }
100                    context.set_global_property_value(T::new(), val)?;
101                    Ok(())
102                },
103            ),
104        )
105        .inspect(|_| panic!("Duplicate global property {}", name));
106}
107
108fn get_global_property_setter(name: &str) -> Option<Arc<PropertySetterFn>> {
109    let properties = GLOBAL_PROPERTIES.lock().unwrap();
110    let tmp = properties.borrow();
111    tmp.get(name).map(Arc::clone)
112}
113
114fn get_global_property_setter_for_config_key(name: &str) -> Option<Arc<PropertySetterFn>> {
115    get_global_property_setter(name).or_else(|| {
116        if name.contains('-') {
117            get_global_property_setter(&name.replace('-', "_"))
118        } else {
119            None
120        }
121    })
122}
123
124/// The trait representing a global property. Do not use this
125/// directly, but instead define global properties with
126/// [`define_global_property!`](crate::define_global_property!).
127///
128/// Validation errors are produced by client code and should be returned as
129/// `Box<dyn std::error::Error + Send + Sync + 'static>`. Ixa wraps those
130/// values in [`IxaError::IllegalGlobalPropertyValue`]
131/// when a global property is set or loaded.
132pub trait GlobalProperty: Any {
133    /// The actual type of the data stored in the global property
134    type Value: Any;
135
136    #[must_use]
137    fn id() -> usize;
138
139    fn new() -> Self;
140
141    #[must_use]
142    fn name() -> &'static str {
143        let full = std::any::type_name::<Self>();
144        full.rsplit("::").next().unwrap()
145    }
146
147    /// A function which validates the global property.
148    ///
149    /// Client code should box any produced error itself.
150    fn validate(value: &Self::Value) -> Result<(), Box<dyn Error + Send + Sync + 'static>>;
151}
152
153pub trait ContextGlobalPropertiesExt: ContextBase {
154    /// Set the value of a global property of type T
155    ///
156    /// # Errors
157    /// Will return an error if an attempt is made to change a value.
158    fn set_global_property_value<T: GlobalProperty + 'static>(
159        &mut self,
160        property: T,
161        value: T::Value,
162    ) -> Result<(), IxaError>;
163
164    /// Return value of global property T
165    #[must_use]
166    fn get_global_property_value<T: GlobalProperty + 'static>(
167        &self,
168        _property: T,
169    ) -> Option<&T::Value>;
170
171    /// Given a file path for a valid json file, deserialize parameter values
172    /// for a given struct T
173    ///
174    /// # Errors
175    ///
176    /// Will return an [`IxaError`] if the `file_path` does not exist or
177    /// cannot be deserialized
178    fn load_parameters_from_json<T: 'static + Debug + DeserializeOwned>(
179        &mut self,
180        file_name: &Path,
181    ) -> Result<T, IxaError> {
182        trace!("Loading parameters from JSON: {file_name:?}");
183        let config_file = fs::File::open(file_name)?;
184        let reader = BufReader::new(config_file);
185        let config = serde_json::from_reader(reader)?;
186        Ok(config)
187    }
188
189    /// Load global properties from a JSON file.
190    ///
191    /// The expected structure is a dictionary with each name being
192    /// the name of the struct prefixed with the crate name, as in:
193    /// `ixa.NumFluVariants` and the value being an object which can
194    /// serde deserialize into the relevant struct. If a package name contains
195    /// hyphens, either the package spelling or Rust's underscore-normalized
196    /// crate spelling can be used.
197    ///
198    /// # Errors
199    /// Will return an [`IxaError`] if:
200    /// * The `file_path` doesn't exist
201    /// * The file isn't valid JSON
202    /// * A specified object doesn't correspond to an existing global property.
203    /// * There are two values for the same object.
204    ///
205    /// Ixa automatically knows about any property defined with
206    /// [`define_global_property!`](crate::define_global_property) so you don't need to register them
207    /// explicitly.
208    ///
209    /// It is possible to call [`Context::load_global_properties()`] multiple
210    /// times with different files as long as the files have disjoint
211    /// sets of properties.
212    fn load_global_properties(&mut self, file_name: &Path) -> Result<(), IxaError>;
213}
214impl ContextGlobalPropertiesExt for Context {
215    fn set_global_property_value<T: GlobalProperty + 'static>(
216        &mut self,
217        _property: T,
218        value: T::Value,
219    ) -> Result<(), IxaError> {
220        T::validate(&value).map_err(|source| IxaError::IllegalGlobalPropertyValue {
221            name: T::name().to_string(),
222            source,
223        })?;
224        let index = T::id();
225        let cell = self.global_properties.get_mut(index).unwrap_or_else(|| {
226            panic!(
227                "No global property found with index = {index:?}. You must use the \
228                 `define_global_property!` macro to create a global property."
229            )
230        });
231        if cell.get().is_some() {
232            // Note: If we change global properties to be mutable, we'll need to
233            // update define_derived_person_property to either handle updates or only
234            // allow immutable properties.
235            return Err(IxaError::EntryAlreadyExists);
236        }
237        let _ = cell.set(Box::new(value));
238        Ok(())
239    }
240
241    fn get_global_property_value<T: GlobalProperty + 'static>(
242        &self,
243        _property: T,
244    ) -> Option<&T::Value> {
245        let index = T::id();
246        self.global_properties
247            .get(index)
248            .unwrap_or_else(|| {
249                panic!(
250                    "No global property found with index = {index:?}. You must use the \
251                     `define_global_property!` macro to create a global property."
252                )
253            })
254            .get()
255            .map(|property| {
256                property.downcast_ref::<T::Value>().expect(
257                    "TypeID does not match global property type. You must use the \
258                     `define_global_property!` macro to create a global property.",
259                )
260            })
261    }
262
263    fn load_global_properties(&mut self, file_name: &Path) -> Result<(), IxaError> {
264        trace!("Loading global properties from {file_name:?}");
265        let config_file = fs::File::open(file_name)?;
266        let reader = BufReader::new(config_file);
267        let val: serde_json::Map<String, serde_json::Value> = serde_json::from_reader(reader)?;
268
269        for (k, v) in val {
270            if let Some(setter) = get_global_property_setter_for_config_key(&k) {
271                setter(self, &k, v)?;
272            } else {
273                return Err(IxaError::NoGlobalProperty { name: k });
274            }
275        }
276
277        Ok(())
278    }
279}
280
281#[cfg(test)]
282mod test {
283    use std::error::Error;
284    use std::fmt;
285    use std::path::PathBuf;
286
287    use serde::{Deserialize, Serialize};
288    use tempfile::tempdir;
289
290    use super::*;
291    use crate::context::Context;
292    use crate::define_global_property;
293    use crate::error::IxaError;
294
295    fn fixture_path(name: &str) -> PathBuf {
296        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
297            .join("integration-tests/fixtures/global-properties")
298            .join(name)
299    }
300
301    #[derive(Debug)]
302    struct InvalidProperty3Value {
303        field_int: u32,
304    }
305
306    impl fmt::Display for InvalidProperty3Value {
307        fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
308            write!(f, "field_int must be zero, got {}", self.field_int)
309        }
310    }
311
312    impl Error for InvalidProperty3Value {}
313
314    #[derive(Serialize, Deserialize, Debug, Clone)]
315    pub struct ParamType {
316        pub days: usize,
317        pub diseases: usize,
318    }
319
320    define_global_property!(DiseaseParams, ParamType);
321
322    #[test]
323    fn set_get_global_property() {
324        let params: ParamType = ParamType {
325            days: 10,
326            diseases: 2,
327        };
328        let params2: ParamType = ParamType {
329            days: 11,
330            diseases: 3,
331        };
332
333        let mut context = Context::new();
334
335        // Set and check the stored value.
336        context
337            .set_global_property_value(DiseaseParams, params.clone())
338            .unwrap();
339        let global_params = context
340            .get_global_property_value(DiseaseParams)
341            .unwrap()
342            .clone();
343        assert_eq!(global_params.days, params.days);
344        assert_eq!(global_params.diseases, params.diseases);
345
346        // Setting again should fail because global properties are immutable.
347        assert!(context
348            .set_global_property_value(DiseaseParams, params2.clone())
349            .is_err());
350
351        // Check that the value is unchanged.
352        let global_params = context
353            .get_global_property_value(DiseaseParams)
354            .unwrap()
355            .clone();
356        assert_eq!(global_params.days, params.days);
357        assert_eq!(global_params.diseases, params.diseases);
358    }
359
360    #[test]
361    fn get_global_propert_missing() {
362        let context = Context::new();
363        let global_params = context.get_global_property_value(DiseaseParams);
364        assert!(global_params.is_none());
365    }
366
367    #[test]
368    fn set_parameters() {
369        let mut context = Context::new();
370        let temp_dir = tempdir().unwrap();
371        let config_path = PathBuf::from(&temp_dir.path());
372        let file_name = "test.json";
373        let file_path = config_path.join(file_name);
374        let config = fs::File::create(config_path.join(file_name)).unwrap();
375
376        let params: ParamType = ParamType {
377            days: 10,
378            diseases: 2,
379        };
380
381        define_global_property!(Parameters, ParamType);
382
383        let _ = serde_json::to_writer(config, &params);
384        let params_json = context
385            .load_parameters_from_json::<ParamType>(&file_path)
386            .unwrap();
387
388        context
389            .set_global_property_value(Parameters, params_json)
390            .unwrap();
391
392        let params_read = context
393            .get_global_property_value(Parameters)
394            .unwrap()
395            .clone();
396        assert_eq!(params_read.days, params.days);
397        assert_eq!(params_read.diseases, params.diseases);
398    }
399
400    #[derive(Serialize, Deserialize)]
401    pub struct Property1Type {
402        field_int: u32,
403        field_str: String,
404    }
405    define_global_property!(Property1, Property1Type);
406
407    #[derive(Serialize, Deserialize)]
408    pub struct Property2Type {
409        field_int: u32,
410    }
411    define_global_property!(Property2, Property2Type);
412
413    #[test]
414    fn read_global_properties() {
415        let mut context = Context::new();
416        let path = fixture_path("global_properties_test1.json");
417        context.load_global_properties(&path).unwrap();
418        let p1 = context.get_global_property_value(Property1).unwrap();
419        assert_eq!(p1.field_int, 1);
420        assert_eq!(p1.field_str, "test");
421        let p2 = context.get_global_property_value(Property2).unwrap();
422        assert_eq!(p2.field_int, 2);
423    }
424
425    #[test]
426    fn read_unknown_property() {
427        let mut context = Context::new();
428        let path = fixture_path("global_properties_missing.json");
429        match context.load_global_properties(&path) {
430            Err(IxaError::NoGlobalProperty { name }) => assert_eq!(name, "ixa.PropertyUnknown"),
431            _ => panic!("Unexpected error type"),
432        }
433    }
434
435    #[test]
436    fn read_malformed_property() {
437        let mut context = Context::new();
438        let path = fixture_path("global_properties_malformed.json");
439        let error = context.load_global_properties(&path);
440        match error {
441            Err(IxaError::JsonError(_)) => {}
442            _ => panic!("Unexpected error type"),
443        }
444    }
445
446    #[test]
447    fn read_duplicate_property() {
448        let mut context = Context::new();
449        let path = fixture_path("global_properties_test1.json");
450        context.load_global_properties(&path).unwrap();
451        let error = context.load_global_properties(&path);
452        match error {
453            Err(IxaError::DuplicateProperty { .. }) => {}
454            _ => panic!("Unexpected error type"),
455        }
456    }
457
458    #[derive(Serialize, Deserialize)]
459    pub struct Property3Type {
460        field_int: u32,
461    }
462    define_global_property!(Property3, Property3Type, |v: &Property3Type| {
463        match v.field_int {
464            0 => Ok(()),
465            _ => Err(Box::new(InvalidProperty3Value {
466                field_int: v.field_int,
467            }) as Box<dyn Error + Send + Sync + 'static>),
468        }
469    });
470
471    #[test]
472    fn validate_property_set_success() {
473        let mut context = Context::new();
474        context
475            .set_global_property_value(Property3, Property3Type { field_int: 0 })
476            .unwrap();
477    }
478
479    #[test]
480    fn validate_property_set_failure() {
481        let mut context = Context::new();
482        let error = context
483            .set_global_property_value(Property3, Property3Type { field_int: 1 })
484            .unwrap_err();
485        assert_eq!(
486            error.to_string(),
487            "illegal value for global property `Property3`: field_int must be zero, got 1"
488        );
489        match error {
490            IxaError::IllegalGlobalPropertyValue { name, source } => {
491                assert_eq!(name, "Property3");
492                assert_eq!(source.to_string(), "field_int must be zero, got 1");
493            }
494            _ => panic!("Unexpected error type"),
495        }
496    }
497
498    #[test]
499    fn validate_property_load_success() {
500        let mut context = Context::new();
501        let path = fixture_path("global_properties_valid.json");
502        context.load_global_properties(&path).unwrap();
503    }
504
505    #[test]
506    fn validate_property_load_failure() {
507        let mut context = Context::new();
508        let path = fixture_path("global_properties_invalid.json");
509        let error = context.load_global_properties(&path).unwrap_err();
510        assert_eq!(
511            error.to_string(),
512            "illegal value for global property `Property3`: field_int must be zero, got 42"
513        );
514        match error {
515            IxaError::IllegalGlobalPropertyValue { name, source } => {
516                assert_eq!(name, "Property3");
517                assert_eq!(source.to_string(), "field_int must be zero, got 42");
518            }
519            _ => panic!("Unexpected error type"),
520        }
521    }
522}
ixa/global_properties.rs

ixa/
global_properties.rs
