[WiP] Experiment with running on Cloudflare Workers

See: https://github.com/kleisauke/cf-worker-wasm-vips

CMakeLists.txt

@@ -15,7 +15,7 @@ if (NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
 endif()
 
 set(ENVIRONMENT "environment" CACHE STRING "Specifies the environment(s) to target.")
-set(ENVIRONMENT_VALUES "web;node" CACHE INTERNAL "List of possible environments.")
+set(ENVIRONMENT_VALUES "web;node;cf" CACHE INTERNAL "List of possible environments.")
 
 set_property(CACHE ENVIRONMENT PROPERTY STRINGS ${ENVIRONMENT_VALUES})
 

build.sh

@@ -564,3 +564,12 @@ node --version
   # Copy versions.json
   cp $TARGET/versions.json $SOURCE_DIR
 )
+
+[ -n "$DISABLE_BINDINGS" ] || [ "$ENVIRONMENT" != "cf" ] || (
+  # Ensure ENVIRONMENT_IS_WORKER == false
+  sed -i 's/"undefined"!=typeof WorkerGlobalScope/false/' $SOURCE_DIR/lib/vips.js
+  # Ensure ENVIRONMENT_IS_WEB == true (`Atomics.wait` cannot be used on Cloudflare workers)
+  sed -i 's/"object"==typeof window/true/' $SOURCE_DIR/lib/vips.js
+  # `navigator.hardwareConcurrency` cannot be used
+  sed -i -e 's/navigator.hardwareConcurrency/1/g' $SOURCE_DIR/lib/vips.js
+)

src/CMakeLists.txt

@@ -93,6 +93,23 @@ if ("web" IN_LIST ENVIRONMENT)
     list(APPEND TARGETS ${PROJECT_NAME}-web ${PROJECT_NAME}-web-es6)
 endif()
 
+if ("cf" IN_LIST ENVIRONMENT)
+    add_executable(${PROJECT_NAME}-cf $<TARGET_OBJECTS:${PROJECT_NAME}>)
+
+    set_target_properties(${PROJECT_NAME}-cf
+            PROPERTIES
+                RUNTIME_OUTPUT_DIRECTORY "${CMAKE_RUNTIME_OUTPUT_DIRECTORY}"
+            )
+
+    target_link_libraries(${PROJECT_NAME}-cf
+            PRIVATE
+                ${VIPS_STATIC_LDFLAGS}
+            )
+
+    list(APPEND TARGETS ${PROJECT_NAME}-cf)
+endif()
+
+
 set(MAIN_COMPILE_OPTIONS
         $<$<BOOL:${ENABLE_MODULES}>:-sMAIN_MODULE=2>
         )
@@ -200,3 +217,22 @@ if ("web" IN_LIST ENVIRONMENT)
                 -sENVIRONMENT=web,deno,worker
             )
 endif()
+
+if ("cf" IN_LIST ENVIRONMENT)
+    # Cloudflare workers:
+    # - disallows dynamic code execution and linking;
+    # - limits memory to 128 MB;
+    # - doesn't support node:worker_threads, nor the Web Workers API;
+    # The last point is a deal-breaker; wasm-vips cannot operate without it.
+    set(CF_LINK_OPTIONS
+            -sENVIRONMENT=web,worker
+            -sEXPORT_ES6
+            -sDYNAMIC_EXECUTION=0
+            -sINITIAL_MEMORY=64MB
+            )
+
+    target_link_options(${PROJECT_NAME}-cf
+            PUBLIC
+                ${CF_LINK_OPTIONS}
+    )
+endif()