feat: remove the infer crate

Cargo.toml

@@ -10,7 +10,7 @@ crate-type = ["cdylib"]
 
 [dependencies]
 env_logger = "0.9.1"
-fontdb = "0.9.1"
+fontdb = "=0.9.3"
 log = "0.4"
 
 serde = { version = "1", features = ["derive"] }
@@ -22,7 +22,6 @@ pathfinder_geometry = "0.5.1"
 pathfinder_content = { version = "0.5.0", default-features = false }
 pathfinder_simd = { version = "0.5.1", features = ["pf-no-simd"] }
 futures = "0.3.21"
-infer = "0.11.0"
 
 [target.'cfg(all(not(all(target_os = "linux", target_arch = "aarch64", target_env = "musl")), not(all(target_os = "windows", target_arch = "aarch64")), not(target_arch = "wasm32")))'.dependencies]
 mimalloc-rust = { version = "0.2" }

src/error.rs

@@ -18,8 +18,8 @@ pub enum Error {
     ZeroSized,
     #[error("Input must be string or Uint8Array")]
     InvalidInput,
-    #[error("Unrecognized image buffer")]
-    UnrecognizedBuffer,
+    #[error("Unsupported image types (currently resvg only supports PNG, JPEG and GIF)")]
+    UnsupportedImage,
 }
 
 #[cfg(not(target_arch = "wasm32"))]

src/lib.rs

@@ -581,9 +581,8 @@ impl Resvg {
     fn resolve_image_inner(&self, href: String, buffer: Vec<u8>) -> Result<(), Error> {
         let resolver = usvg::ImageHrefResolver::default_data_resolver();
         let options = self.js_options.to_usvg_options();
-        let mime = infer::get(&buffer)
-            .ok_or_else(|| Error::UnrecognizedBuffer)?
-            .to_string();
+        let mime = MimeType::parse(&buffer)?.mime_type().to_string();
+
         for node in self.tree.root.descendants() {
             if let NodeKind::Image(i) = &mut *node.borrow_mut() {
                 let matched = if let ImageKind::RAW(_, _, data) = &mut i.kind {
@@ -648,3 +647,33 @@ fn points_to_rect(min: usvg::Point<f64>, max: usvg::Point<f64>) -> RectF {
     let max = Vector2F::new(max.x as f32, max.y as f32);
     RectF::new(min, max - min)
 }
+
+// Detects the file type by magic number.
+// Currently resvg only supports the following types of files.
+pub enum MimeType {
+    Png,
+    Jpeg,
+    Gif,
+}
+
+impl MimeType {
+    pub fn parse(buffer: &[u8]) -> Result<Self, Error> {
+        if buffer.len() < 4 {
+            return Err(Error::UnsupportedImage);
+        }
+        Ok(match &buffer[0..4] {
+            [0x89, 0x50, 0x4E, 0x47] => MimeType::Png,
+            [0xFF, 0xD8, 0xFF, _] => MimeType::Jpeg,
+            [0x47, 0x49, 0x46, _] => MimeType::Gif,
+            _ => return Err(Error::UnsupportedImage),
+        })
+    }
+
+    pub fn mime_type(&self) -> &'static str {
+        match self {
+            MimeType::Png => "image/png",
+            MimeType::Gif => "image/gif",
+            _ => "image/jpeg",
+        }
+    }
+}