first pass of merging in warp (doesn't build)

app/src/util/image.rs

@@ -3,13 +3,39 @@
 //! This module provides common functionality for processing images before they are
 //! sent to the AI agent, whether attached by the user or read via the read_files tool.
 
+use std::path::Path;
+
 use image::{GenericImageView, ImageError};
+use mime_guess::from_path;
 
 /// Max image size is 3.75 MB.
 /// The max size of an image we will send is 5MB. However, due to the 33% inflation of Base64, this means
 /// the largest size a user can attach is actually ~3.75MB.
 pub const MAX_IMAGE_SIZE_BYTES: usize = 3750 * 1000;
 
+/// Cap on individual image bytes when relaying a dropped/pasted image to a
+/// CLI agent (Claude Code etc.) via the system clipboard. CLI agents handle
+/// their own compression, so this limit only exists to keep us from loading
+/// arbitrarily large files into memory.
+pub const MAX_IMAGE_SIZE_BYTES_FOR_CLI_AGENT: usize = 500 * 1_000_000;
+
+/// How many leading bytes of a file are enough for `infer_mime_type` to
+/// match a magic-number signature. Callers that already have the full bytes
+/// in memory should pass only the first `MIME_SNIFF_BYTES` to avoid handing
+/// arbitrarily large slices to the sniffer.
+pub const MIME_SNIFF_BYTES: usize = 8 * 1024;
+
+/// Returns the MIME type for `path`, preferring magic-byte detection from
+/// `file_bytes` and falling back to the path's extension when the magic
+/// bytes don't yield a confident match. Falls all the way back to
+/// `application/octet-stream`. `file_bytes` only needs to contain the first
+/// `MIME_SNIFF_BYTES` of the file for the magic-number check.
+pub fn infer_mime_type(path: &Path, file_bytes: &[u8]) -> String {
+    infer::get(file_bytes)
+        .map(|kind| kind.mime_type().to_string())
+        .unwrap_or_else(|| from_path(path).first_or_octet_stream().to_string())
+}
+
 /// 1.15 Megapixels
 pub const MAX_IMAGE_PIXELS: f64 = 1150. * 1000.;