Simplify cache configuration API

A new `cache_config(Option<CacheConfig>)` method replaces multiple methods
for controlling module caching. Now `None` disables caching, and users can
directly provide a cache config or load one from a file.

Author: benbrandt

crates/bench-api/src/lib.rs

@@ -436,7 +436,7 @@ impl BenchState {
     ) -> Result<Self> {
         let mut config = options.config(None)?;
         // NB: always disable the compilation cache.
-        config.disable_cache();
+        config.cache_config(None);
         let engine = Engine::new(&config)?;
         let mut linker = Linker::<HostState>::new(&engine);
 

crates/c-api/src/config.rs

@@ -211,12 +211,17 @@ pub unsafe extern "C" fn wasmtime_config_cache_config_load(
     c: &mut wasm_config_t,
     filename: *const c_char,
 ) -> Option<Box<wasmtime_error_t>> {
+    use std::path::Path;
+
+    use wasmtime::CacheConfig;
+
     handle_result(
         if filename.is_null() {
-            c.config.cache_config_load_default()
+            CacheConfig::from_file(None).map(|cfg| c.config.cache_config(Some(cfg)))
         } else {
             match CStr::from_ptr(filename).to_str() {
-                Ok(s) => c.config.cache_config_load(s),
+                Ok(s) => CacheConfig::from_file(Some(&Path::new(s)))
+                    .map(|cfg| c.config.cache_config(Some(cfg))),
                 Err(e) => Err(e.into()),
             }
         },

crates/cache/src/config.rs

@@ -346,7 +346,23 @@ impl CacheConfig {
         conf
     }
 
-    /// Parses cache configuration from the file specified
+    /// Loads cache configuration specified at `path`.
+    ///
+    /// This method will read the file specified by `path` on the filesystem and
+    /// attempt to load cache configuration from it. This method can also fail
+    /// due to I/O errors, misconfiguration, syntax errors, etc. For expected
+    /// syntax in the configuration file see the [documentation online][docs].
+    ///
+    /// Passing in `None` loads cache configuration from the system default path.
+    /// This is located, for example, on Unix at `$HOME/.config/wasmtime/config.toml`
+    /// and is typically created with the `wasmtime config new` command.
+    ///
+    /// # Errors
+    ///
+    /// This method can fail due to any error that happens when loading the file
+    /// pointed to by `path` and attempting to load the cache configuration.
+    ///
+    /// [docs]: https://bytecodealliance.github.io/wasmtime/cli-cache.html
     pub fn from_file(config_file: Option<&Path>) -> Result<Self> {
         let mut config = Self::load_and_parse_file(config_file)?;
         config.validate_or_default()?;

crates/cli-flags/src/lib.rs

@@ -737,10 +737,12 @@ impl CommonOptions {
         if self.codegen.cache != Some(false) {
             match &self.codegen.cache_config {
                 Some(path) => {
-                    config.cache_config_load(path)?;
+                    config.cache_config(Some(wasmtime::CacheConfig::from_file(Some(Path::new(
+                        path,
+                    )))?));
                 }
                 None => {
-                    config.cache_config_load_default()?;
+                    config.cache_config(Some(wasmtime::CacheConfig::from_file(None)?));
                 }
             }
         }

crates/wasmtime/src/config.rs

@@ -1371,88 +1371,25 @@ impl Config {
 
     /// Set a custom cache configuration.
     ///
-    /// If you want to load the cache configuration from a file, use [`Config::cache_config_load`]
-    /// or [`Config::cache_config_load_default`] for the default enabled configuration.
+    /// If you want to load the cache configuration from a file, use [`CacheConfig::from_file`].
+    /// You can call [`CacheConfig::from_file(None)`] for the default, enabled configuration.
     ///
-    /// By default cache configuration is not enabled or loaded.
+    /// If you want to disable the cache, you can call this method with `None`.
     ///
-    /// This method is only available when the `cache` feature of this crate is
-    /// enabled.
-    ///
-    /// [docs]: https://bytecodealliance.github.io/wasmtime/cli-cache.html
-    #[cfg(feature = "cache")]
-    pub fn cache_config(&mut self, cache_config: CacheConfig) -> &mut Self {
-        self.cache_config = cache_config;
-        self
-    }
-
-    /// Loads cache configuration specified at `path`.
-    ///
-    /// This method will read the file specified by `path` on the filesystem and
-    /// attempt to load cache configuration from it. This method can also fail
-    /// due to I/O errors, misconfiguration, syntax errors, etc. For expected
-    /// syntax in the configuration file see the [documentation online][docs].
-    ///
-    /// By default cache configuration is not enabled or loaded.
+    /// By default, new configs do not have caching enabled.
+    /// Every call to [`Module::new(my_wasm)`][crate::Module::new] will recompile `my_wasm`,
+    /// even when it is unchanged, unless an enabled `CacheConfig` is provided.
     ///
     /// This method is only available when the `cache` feature of this crate is
     /// enabled.
     ///
-    /// # Errors
-    ///
-    /// This method can fail due to any error that happens when loading the file
-    /// pointed to by `path` and attempting to load the cache configuration.
-    ///
     /// [docs]: https://bytecodealliance.github.io/wasmtime/cli-cache.html
     #[cfg(feature = "cache")]
-    pub fn cache_config_load(&mut self, path: impl AsRef<Path>) -> Result<&mut Self> {
-        self.cache_config = CacheConfig::from_file(Some(path.as_ref()))?;
-        Ok(self)
-    }
-
-    /// Disable caching.
-    ///
-    /// Every call to [`Module::new(my_wasm)`][crate::Module::new] will
-    /// recompile `my_wasm`, even when it is unchanged.
-    ///
-    /// By default, new configs do not have caching enabled. This method is only
-    /// useful for disabling a previous cache configuration.
-    ///
-    /// This method is only available when the `cache` feature of this crate is
-    /// enabled.
-    #[cfg(feature = "cache")]
-    pub fn disable_cache(&mut self) -> &mut Self {
-        self.cache_config = CacheConfig::new_cache_disabled();
+    pub fn cache_config(&mut self, cache_config: Option<CacheConfig>) -> &mut Self {
+        self.cache_config = cache_config.unwrap_or_else(|| CacheConfig::new_cache_disabled());
         self
     }
 
-    /// Loads cache configuration from the system default path.
-    ///
-    /// This commit is the same as [`Config::cache_config_load`] except that it
-    /// does not take a path argument and instead loads the default
-    /// configuration present on the system. This is located, for example, on
-    /// Unix at `$HOME/.config/wasmtime/config.toml` and is typically created
-    /// with the `wasmtime config new` command.
-    ///
-    /// By default cache configuration is not enabled or loaded.
-    ///
-    /// This method is only available when the `cache` feature of this crate is
-    /// enabled.
-    ///
-    /// # Errors
-    ///
-    /// This method can fail due to any error that happens when loading the
-    /// default system configuration. Note that it is not an error if the
-    /// default config file does not exist, in which case the default settings
-    /// for an enabled cache are applied.
-    ///
-    /// [docs]: https://bytecodealliance.github.io/wasmtime/cli-cache.html
-    #[cfg(feature = "cache")]
-    pub fn cache_config_load_default(&mut self) -> Result<&mut Self> {
-        self.cache_config = CacheConfig::from_file(None)?;
-        Ok(self)
-    }
-
     /// Sets a custom memory creator.
     ///
     /// Custom memory creators are used when creating host `Memory` objects or when

crates/wasmtime/src/engine/serialization.rs

@@ -446,7 +446,7 @@ impl Metadata<'_> {
 #[cfg(test)]
 mod test {
     use super::*;
-    use crate::{Config, Module, OptLevel};
+    use crate::{CacheConfig, Config, Module, OptLevel};
     use std::{
         collections::hash_map::DefaultHasher,
         hash::{Hash, Hasher},
@@ -664,7 +664,7 @@ Caused by:
         )?;
         let mut cfg = Config::new();
         cfg.cranelift_opt_level(OptLevel::None)
-            .cache_config_load(&config_path)?;
+            .cache_config(Some(CacheConfig::from_file(Some(&config_path))?));
         let engine = Engine::new(&cfg)?;
         Module::new(&engine, "(module (func))")?;
         assert_eq!(engine.config().cache_config.cache_hits(), 0);
@@ -675,7 +675,7 @@ Caused by:
 
         let mut cfg = Config::new();
         cfg.cranelift_opt_level(OptLevel::Speed)
-            .cache_config_load(&config_path)?;
+            .cache_config(Some(CacheConfig::from_file(Some(&config_path))?));
         let engine = Engine::new(&cfg)?;
         Module::new(&engine, "(module (func))")?;
         assert_eq!(engine.config().cache_config.cache_hits(), 0);
@@ -686,7 +686,7 @@ Caused by:
 
         let mut cfg = Config::new();
         cfg.cranelift_opt_level(OptLevel::SpeedAndSize)
-            .cache_config_load(&config_path)?;
+            .cache_config(Some(CacheConfig::from_file(Some(&config_path))?));
         let engine = Engine::new(&cfg)?;
         Module::new(&engine, "(module (func))")?;
         assert_eq!(engine.config().cache_config.cache_hits(), 0);
@@ -696,7 +696,8 @@ Caused by:
         assert_eq!(engine.config().cache_config.cache_misses(), 1);
 
         let mut cfg = Config::new();
-        cfg.debug_info(true).cache_config_load(&config_path)?;
+        cfg.debug_info(true)
+            .cache_config(Some(CacheConfig::from_file(Some(&config_path))?));
         let engine = Engine::new(&cfg)?;
         Module::new(&engine, "(module (func))")?;
         assert_eq!(engine.config().cache_config.cache_hits(), 0);
@@ -771,7 +772,7 @@ Caused by:
             ),
         )?;
         let mut cfg = Config::new();
-        cfg.cache_config_load(&config_path)?;
+        cfg.cache_config(Some(CacheConfig::from_file(Some(&config_path))?));
         let engine = Engine::new(&cfg)?;
         Component::new(&engine, "(component (core module (func)))")?;
         assert_eq!(engine.config().cache_config.cache_hits(), 0);

examples/fast_compilation.rs

@@ -3,14 +3,14 @@
 //! If your application design is compatible with pre-compiling Wasm programs,
 //! prefer doing that.
 
-use wasmtime::{Config, Engine, Result, Strategy};
+use wasmtime::{CacheConfig, Config, Engine, Result, Strategy};
 
 fn main() -> Result<()> {
     let mut config = Config::new();
 
     // Enable the compilation cache, using the default cache configuration
     // settings.
-    config.cache_config_load_default()?;
+    config.cache_config(Some(CacheConfig::from_file(None)?));
 
     // Enable Winch, Wasmtime's baseline compiler.
     config.strategy(Strategy::Winch);

src/commands/explore.rs

@@ -51,7 +51,7 @@ impl ExploreCommand {
         let clif_dir = if let Some(Strategy::Cranelift) | None = self.common.codegen.compiler {
             let clif_dir = tempdir()?;
             config.emit_clif(clif_dir.path());
-            config.disable_cache(); // cache does not emit clif
+            config.cache_config(None); // cache does not emit clif
             Some(clif_dir)
         } else {
             None