From e42e497ae8a9d525a46da55fa3eba798fc575360 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Thu, 24 Jul 2025 10:45:19 +0200
Subject: [PATCH] Prescient

---
 Cargo.lock                   |  5 +++--
 Cargo.toml                   |  2 +-
 crates/typst-cli/Cargo.toml  |  1 +
 crates/typst-cli/src/main.rs | 13 +++++++++++++
 4 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index 7d12aa699..d16880724 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -451,7 +451,7 @@ checksum = "5b63caa9aa9397e2d9480a9b13673856c78d8ac123288526c37d7839f2a86990"
 [[package]]
 name = "comemo"
 version = "0.4.0"
-source = "git+https://github.com/typst/comemo?rev=70c0307#70c03075453deda2b2cc592ee8676edfe7962804"
+source = "git+https://github.com/typst/comemo?rev=499bce5#499bce59ae44af9e61dc106b6b1663a45669b87e"
 dependencies = [
  "bumpalo",
  "comemo-macros",
@@ -463,7 +463,7 @@ dependencies = [
 [[package]]
 name = "comemo-macros"
 version = "0.4.0"
-source = "git+https://github.com/typst/comemo?rev=70c0307#70c03075453deda2b2cc592ee8676edfe7962804"
+source = "git+https://github.com/typst/comemo?rev=499bce5#499bce59ae44af9e61dc106b6b1663a45669b87e"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -2935,6 +2935,7 @@ dependencies = [
  "dirs",
  "ecow",
  "fs_extra",
+ "memmap2",
  "notify",
  "open",
  "parking_lot",
diff --git a/Cargo.toml b/Cargo.toml
index 6c99b2131..fe26d3d90 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -165,4 +165,4 @@ uninlined_format_args = "warn"
 wildcard_in_or_patterns = "allow"
 
 [patch.crates-io]
-comemo = { git = "https://github.com/typst/comemo", rev = "70c0307" }
+comemo = { git = "https://github.com/typst/comemo", rev = "499bce5" }
diff --git a/crates/typst-cli/Cargo.toml b/crates/typst-cli/Cargo.toml
index 792cabae1..e1c4924c7 100644
--- a/crates/typst-cli/Cargo.toml
+++ b/crates/typst-cli/Cargo.toml
@@ -56,6 +56,7 @@ toml = { workspace = true }
 ureq = { workspace = true }
 xz2 = { workspace = true, optional = true }
 zip = { workspace = true, optional = true }
+memmap2 = "*"
 
 [build-dependencies]
 chrono = { workspace = true }
diff --git a/crates/typst-cli/src/main.rs b/crates/typst-cli/src/main.rs
index 4774dd43b..7ad45d257 100644
--- a/crates/typst-cli/src/main.rs
+++ b/crates/typst-cli/src/main.rs
@@ -47,6 +47,13 @@ static ARGS: LazyLock<CliArguments> = LazyLock::new(|| {
 
 /// Entry point.
 fn main() -> ExitCode {
+    let mut prescient = false;
+    if let Ok(file) = std::fs::File::open("comemo-sink") {
+        let mmap = Box::leak(Box::new(unsafe { memmap2::Mmap::map(&file).unwrap() }));
+        comemo::put_prescience(&*mmap);
+        prescient = true;
+    }
+
     // Handle SIGPIPE
     // https://stackoverflow.com/questions/65755853/simple-word-count-rust-program-outputs-valid-stdout-but-panicks-when-piped-to-he/65760807
     sigpipe::reset();
@@ -58,6 +65,12 @@ fn main() -> ExitCode {
         print_error(msg.message()).expect("failed to print error");
     }
 
+    if !prescient {
+        let file = std::fs::File::create("comemo-sink").unwrap();
+        let sink = std::io::BufWriter::new(file);
+        comemo::write_prescience(sink);
+    }
+
     EXIT.with(|cell| cell.get())
 }