From a9cc4631ca4b5e2bb64943435d0d8242292b168d Mon Sep 17 00:00:00 2001
From: Curran McConnell <curran.mcconnell@protonmail.com>
Date: Thu, 7 Sep 2023 23:41:33 -0400
Subject: [PATCH] fix(ext/node/ops/zlib/brotli): Allow decompressing more than
 4096 bytes (#20301)

Fixes https://github.com/denoland/deno/issues/19816

In that issue, I suggest switching over the other brotli functionality
to the Rust API provided by the `brotli` crate. Here, I only do that
with the `brotli_decompress` function to fix the bug with buffers longer
than 4096 bytes.
---
 cli/tests/unit_node/zlib_test.ts |  7 +++++++
 ext/node/ops/zlib/brotli.rs      | 36 ++++++--------------------------
 2 files changed, 13 insertions(+), 30 deletions(-)

diff --git a/cli/tests/unit_node/zlib_test.ts b/cli/tests/unit_node/zlib_test.ts
index 6b09c50b08..b878b7cc32 100644
--- a/cli/tests/unit_node/zlib_test.ts
+++ b/cli/tests/unit_node/zlib_test.ts
@@ -62,6 +62,13 @@ Deno.test("brotli compression", async () => {
   }
 });
 
+Deno.test("brotli end-to-end with 4097 bytes", () => {
+  const a = "a".repeat(4097);
+  const compressed = brotliCompressSync(a);
+  const decompressed = brotliDecompressSync(compressed);
+  assertEquals(decompressed.toString(), a);
+});
+
 Deno.test(
   "zlib create deflate with dictionary",
   { sanitizeResources: false },
diff --git a/ext/node/ops/zlib/brotli.rs b/ext/node/ops/zlib/brotli.rs
index f3b5001aab..b4d9709702 100644
--- a/ext/node/ops/zlib/brotli.rs
+++ b/ext/node/ops/zlib/brotli.rs
@@ -4,6 +4,7 @@ use brotli::ffi::compressor::*;
 use brotli::ffi::decompressor::ffi::interface::BrotliDecoderResult;
 use brotli::ffi::decompressor::ffi::BrotliDecoderState;
 use brotli::ffi::decompressor::*;
+use brotli::Decompressor;
 use deno_core::error::type_error;
 use deno_core::error::AnyError;
 use deno_core::op;
@@ -11,6 +12,7 @@ use deno_core::JsBuffer;
 use deno_core::OpState;
 use deno_core::Resource;
 use deno_core::ToJsBuffer;
+use std::io::Read;
 
 fn encoder_mode(mode: u32) -> Result<BrotliEncoderMode, AnyError> {
   if mode > 6 {
@@ -214,36 +216,10 @@ pub fn op_brotli_compress_stream_end(
 }
 
 fn brotli_decompress(buffer: &[u8]) -> Result<ToJsBuffer, AnyError> {
-  let in_buffer = buffer.as_ptr();
-  let in_size = buffer.len();
-
-  let mut out = vec![0u8; 4096];
-  loop {
-    let out_buffer = out.as_mut_ptr();
-    let mut out_size = out.len();
-    // SAFETY: TODO(littledivy)
-    match unsafe {
-      CBrotliDecoderDecompress(
-        in_size,
-        in_buffer,
-        &mut out_size as *mut usize,
-        out_buffer,
-      )
-    } {
-      BrotliDecoderResult::BROTLI_DECODER_RESULT_SUCCESS => {
-        out.truncate(out_size);
-        return Ok(out.into());
-      }
-      BrotliDecoderResult::BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT => {
-        let new_size = out.len() * 2;
-        if new_size < out.len() {
-          return Err(type_error("Failed to decompress"));
-        }
-        out.resize(new_size, 0);
-      }
-      _ => return Err(type_error("Failed to decompress")),
-    }
-  }
+  let mut output = Vec::with_capacity(4096);
+  let mut decompressor = Decompressor::new(buffer, buffer.len());
+  decompressor.read_to_end(&mut output)?;
+  Ok(output.into())
 }
 
 #[op]