Use git apply patch to fix uWebsockets crash, previously fixed by python script in #344 (#507)

Previously we downloaded a tarball release of uWebSockets and then patched the code to fix a crash issue. The patch was executed by a custom python script which somewhat blindly overwrote at set of line numbers in the file. See PR #344

Git apply patch wasn't used because it requires a initialized git repo to work. Cloning the the uWebsockets repo with history and then checking out to an older commit would explode the disk usage, causing parition exhaustion issues on Windows, so we were forced to use the non-git-initialized tarball.

Thankfully I found a way to fetch a repo at a specific commit, removing the overhead of cloning all of the history. This change updates the cmake download step for uWebSockets to fetch the commit instead of downloading a tarball. With a git initialized repo we can our change with a far safer git apply patch instead of our custom python script, akin to what was done for boringSSL in PR #485

Author: DellaBitta

cmake/external/boringssl.cmake

@@ -21,14 +21,14 @@ endif()
 set(patch_file 
   ${CMAKE_CURRENT_LIST_DIR}/../../scripts/git/patches/boringssl/0001-disable-C4255-converting-empty-params-to-void.patch)
 
-set(commit_tag 83da28a68f32023fd3b95a8ae94991a07b1f6c62)
+set(boringssl_commit_tag 83da28a68f32023fd3b95a8ae94991a07b1f6c62)
 
 ExternalProject_Add(
   boringssl
 
   DOWNLOAD_COMMAND 
     COMMAND git init boringssl
-    COMMAND cd boringssl && git fetch --depth=1 https://github.com/google/boringssl ${commit_tag} && git reset --hard FETCH_HEAD
+    COMMAND cd boringssl && git fetch --depth=1 https://github.com/google/boringssl.git ${boringssl_commit_tag} && git reset --hard FETCH_HEAD
 
   PATCH_COMMAND git apply ${patch_file} && git gc --aggressive
   PREFIX ${PROJECT_BINARY_DIR}

cmake/external/uWebSockets.cmake

@@ -18,17 +18,19 @@ if(TARGET uWebSockets OR NOT DOWNLOAD_UWEBSOCKETS)
   return()
 endif()
 
-set(commit 4d94401b9c98346f9afd838556fdc7dce30561eb)
+set(uwebsockets_commit_tag 4d94401b9c98346f9afd838556fdc7dce30561eb)
+set(patch_file 
+  ${CMAKE_CURRENT_LIST_DIR}/../../scripts/git/patches/uWebSockets/0001-fix-want-write-crash.patch)
 
 ExternalProject_Add(
   uWebSockets
 
-  DOWNLOAD_DIR ${FIREBASE_DOWNLOAD_DIR}
-  DOWNLOAD_NAME uWebSockets-${commit}.tar.gz
-  URL https://github.com/uNetworking/uWebSockets/archive/${commit}.tar.gz
+  DOWNLOAD_COMMAND 
+    COMMAND git init uWebSockets
+    COMMAND cd uWebSockets && git fetch --depth=1 https://github.com/uNetworking/uWebSockets.git ${uwebsockets_commit_tag} && git reset --hard FETCH_HEAD
 
+  PATCH_COMMAND git apply ${patch_file} && git gc --aggressive
   PREFIX ${PROJECT_BINARY_DIR}
-
   CONFIGURE_COMMAND ""
   BUILD_COMMAND ""
   INSTALL_COMMAND ""

cmake/external_rules.cmake

@@ -121,16 +121,6 @@ function(download_external_sources)
       file(INSTALL "${PROJECT_SOURCE_DIR}/cmake/external/leveldb.cmake"
            DESTINATION "${PROJECT_BINARY_DIR}/external/src/firestore/cmake/external")
     endif()
-
-    execute_process(
-      COMMAND ${FIREBASE_PYTHON_EXECUTABLE} "${PROJECT_SOURCE_DIR}/scripts/patch_websockets.py" 
-              "-file" "${PROJECT_BINARY_DIR}/external/src/uWebSockets/src/Socket.h"
-              "-cmakefile" "${PROJECT_SOURCE_DIR}/cmake/external/uWebSockets.cmake" 
-      RESULT_VARIABLE STATUS)
-      if( STATUS AND NOT STATUS EQUAL 0 )
-        message(FATAL_ERROR "FAILED to patch uWebsockets/src/Socket.h")
-        message(FATAL_ERROR "see cmake/external_rules.cmake.")
-      endif()
   endif()
 endfunction()
 

scripts/git/patches/uWebsockets/0001-fix-want-write-crash.patch

@@ -0,0 +1,59 @@
+From d868ac6f2ce8c6ba8359e33616caeb889e0c57e7 Mon Sep 17 00:00:00 2001
+From: "google.com" <google.com>
+Date: Wed, 7 Jul 2021 19:00:49 -0400
+Subject: [PATCH] fix want_write crash
+
+---
+ src/Socket.h | 34 ++++++++++++++++++----------------
+ 1 file changed, 18 insertions(+), 16 deletions(-)
+
+diff --git a/src/Socket.h b/src/Socket.h
+index 2179ff8..521e798 100644
+--- a/src/Socket.h
++++ b/src/Socket.h
+@@ -306,24 +306,26 @@ protected:
+         if (messageQueue.empty()) {
+ 
+             if (ssl) {
+-                sent = SSL_write(ssl, message->data, message->length);
+-                if (sent == (ssize_t) message->length) {
+-                    wasTransferred = false;
+-                    return true;
+-                } else if (sent < 0) {
+-                    switch (SSL_get_error(ssl, sent)) {
+-                    case SSL_ERROR_WANT_READ:
+-                        break;
+-                    case SSL_ERROR_WANT_WRITE:
+-                        if ((getPoll() & UV_WRITABLE) == 0) {
+-                            setPoll(getPoll() | UV_WRITABLE);
+-                            changePoll(this);
++                /* BEG Patched by firebase-cpp-sdk 00001-fix-want-write-crash.patch */
++                bool continue_loop = true;
++                do {
++                    sent = SSL_write(ssl, message->data, message->length);
++                    if (sent == (ssize_t) message->length) {
++                        wasTransferred = false;
++                        return true;
++                    } else if (sent < 0) {
++                        switch (SSL_get_error(ssl, sent)) {
++                        case SSL_ERROR_WANT_READ:
++                            continue_loop = false;
++                            break;
++                        case SSL_ERROR_WANT_WRITE:
++                            break;
++                        default:
++                            return false;
+                         }
+-                        break;
+-                    default:
+-                        return false;
+                     }
+-                }
++                } while (continue_loop);
++                /* END Patched by firebase-cpp-sdk 00001-fix-want-write-crash.patch */
+             } else {
+                 sent = ::send(getFd(), message->data, message->length, MSG_NOSIGNAL);
+                 if (sent == (ssize_t) message->length) {
+-- 
+2.32.0.93.g670b81a890-goog
+