Updating the EngineFinder.cmake for the AutomatedTesting project to use the engines_path key

AutomatedTesting/EngineFinder.cmake

@@ -20,33 +20,46 @@ if(json_error)
     message(FATAL_ERROR "Unable to read key 'engine' from 'project.json', error: ${json_error}")
 endif()
 
-# Read the list of paths from ~.o3de/o3de_manifest.json
-file(TO_CMAKE_PATH "$ENV{USERPROFILE}" home_directory) # Windows
-if((NOT home_directory) OR (NOT EXISTS ${home_directory}))
-    file(TO_CMAKE_PATH "$ENV{HOME}" home_directory)# Unix
+if(DEFINED ENV{USERPROFILE} AND EXISTS $ENV{USERPROFILE})
+    set(manifest_path $ENV{USERPROFILE}/.o3de/o3de_manifest.json) # Windows
+else()
+    set(manifest_path $ENV{HOME}/.o3de/o3de_manifest.json) # Unix
 endif()
 
-if (NOT home_directory)
-    message(FATAL_ERROR "Cannot find user home directory, the o3de manifest cannot be found")
-endif()
-# Set manifest path to path in the user home directory
-set(manifest_path ${home_directory}/.o3de/o3de_manifest.json)
-
+# Read the ~/.o3de/o3de_manifest.json file and look through the 'engines_path' object.
+# Find a key that matches LY_ENGINE_NAME_TO_USE and use that as the engine path.
 if(EXISTS ${manifest_path})
     file(READ ${manifest_path} manifest_json)
-    string(JSON engines_count ERROR_VARIABLE json_error LENGTH ${manifest_json} engines)
+
+    string(JSON engines_path_count ERROR_VARIABLE json_error LENGTH ${manifest_json} engines_path)
     if(json_error)
-        message(FATAL_ERROR "Unable to read key 'engines' from '${manifest_path}', error: ${json_error}")
+        message(FATAL_ERROR "Unable to read key 'engines_path' from '${manifest_path}', error: ${json_error}")
     endif()
 
-    math(EXPR engines_count "${engines_count}-1")
-    foreach(engine_path_index RANGE ${engines_count})
-        string(JSON engine_path ERROR_VARIABLE json_error GET ${manifest_json} engines ${engine_path_index})
-        if(${json_error})
-            message(FATAL_ERROR "Unable to read engines[${engine_path_index}] '${manifest_path}', error: ${json_error}")
+    string(JSON engines_path_type ERROR_VARIABLE json_error TYPE ${manifest_json} engines_path)
+    if(json_error OR NOT ${engines_path_type} STREQUAL "OBJECT")
+        message(FATAL_ERROR "Type of 'engines_path' in '${manifest_path}' is not a JSON Object, error: ${json_error}")
+    endif()
+
+    math(EXPR engines_path_count "${engines_path_count}-1")
+    foreach(engine_path_index RANGE ${engines_path_count})
+        string(JSON engine_name ERROR_VARIABLE json_error MEMBER ${manifest_json} engines_path ${engine_path_index})
+        if(json_error)
+            message(FATAL_ERROR "Unable to read 'engines_path/${engine_path_index}' from '${manifest_path}', error: ${json_error}")
         endif()
-        if(engine_path)
-            list(APPEND CMAKE_MODULE_PATH "${engine_path}/cmake")
+
+        if(LY_ENGINE_NAME_TO_USE STREQUAL engine_name)
+            string(JSON engine_path ERROR_VARIABLE json_error GET ${manifest_json} engines_path ${engine_name})
+            if(json_error)
+                message(FATAL_ERROR "Unable to read value from 'engines_path/${engine_name}', error: ${json_error}")
+            endif()
+
+            if(engine_path)
+                list(APPEND CMAKE_MODULE_PATH "${engine_path}/cmake")
+                break()
+            endif()
         endif()
     endforeach()
+else()
+    message(FATAL_ERROR "Engine registration is required before configuring a project.  Please register an engine by running 'scripts/o3de register --this-engine'")
 endif()