From c6f97a0b7cd353ee95b4de1d4c4ad0336eb529b5 Mon Sep 17 00:00:00 2001
From: Thomas Willson <willsont@curtisinst.com>
Date: Sat, 18 Sep 2021 20:17:46 -0700
Subject: [PATCH] Allow merge of C_Cpp_Properties & configuration provider.

Adds a configuration that enables the include paths, defines, and forced
includes from `c_cpp_properties.json` to be merged with those provided
by a configuration provider.

This is especially helpful for projects that use unsupported compilers
as defines/includePaths/forcedIncludes can be provided as shims for
intellisense.
---
 Extension/c_cpp_properties.schema.json        |  4 +++
 Extension/src/LanguageServer/client.ts        | 31 +++++++++++++++++--
 .../src/LanguageServer/configurations.ts      |  1 +
 3 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/Extension/c_cpp_properties.schema.json b/Extension/c_cpp_properties.schema.json
index 380b4adda5..5e4a4a6354 100644
--- a/Extension/c_cpp_properties.schema.json
+++ b/Extension/c_cpp_properties.schema.json
@@ -155,6 +155,10 @@
                         "description": "The id of a VS Code extension that can provide IntelliSense configuration information for source files.",
                         "type": "string"
                     },
+                    "mergeConfigurations": {
+                        "description": "Set to `true` to merge include paths, defines, and forced includes with those from a configuration provider.",
+                        "type": "boolean"
+                    },
                     "browse": {
                         "type": "object",
                         "properties": {
diff --git a/Extension/src/LanguageServer/client.ts b/Extension/src/LanguageServer/client.ts
index 703cbbff82..6e9b066246 100644
--- a/Extension/src/LanguageServer/client.ts
+++ b/Extension/src/LanguageServer/client.ts
@@ -1797,9 +1797,36 @@ export class DefaultClient implements Client {
                             const candidate: string = response.candidates[i];
                             const tuUri: vscode.Uri = vscode.Uri.parse(candidate);
                             if (await provider.canProvideConfiguration(tuUri, tokenSource.token)) {
-                                const configs: SourceFileConfigurationItem[] = await provider.provideConfigurations([tuUri], tokenSource.token);
+                                const configs: util.Mutable<SourceFileConfigurationItem>[] = await provider.provideConfigurations([tuUri], tokenSource.token);
                                 if (configs && configs.length > 0 && configs[0]) {
-                                    return configs;
+                                    const fileConfiguration: configs.Configuration | undefined = this.configuration.CurrentConfiguration;
+                                    if (fileConfiguration?.mergeConfigurations ?? false) {
+                                        configs.forEach(config => {
+                                            fileConfiguration?.includePath?.forEach(p => {
+                                                if (!config.configuration.includePath.includes(p)) {
+                                                    config.configuration.includePath.push(p);
+                                                }
+                                            });
+
+                                            fileConfiguration?.defines?.forEach(d => {
+                                                if (!config.configuration.defines.includes(d)) {
+                                                    config.configuration.defines.push(d);
+                                                }
+                                            });
+
+                                            if (!config.configuration.forcedInclude) {
+                                                config.configuration.forcedInclude = [];
+                                            }
+
+                                            fileConfiguration?.forcedInclude?.forEach(i => {
+                                                if (!config.configuration.forcedInclude?.includes(i) ?? false) {
+                                                    config.configuration.forcedInclude?.push(i);
+                                                }
+                                            });
+                                        });
+                                    }
+
+                                    return configs as SourceFileConfigurationItem[];
                                 }
                             }
                             if (tokenSource.token.isCancellationRequested) {
diff --git a/Extension/src/LanguageServer/configurations.ts b/Extension/src/LanguageServer/configurations.ts
index 9faa5d67c3..14f38860e3 100644
--- a/Extension/src/LanguageServer/configurations.ts
+++ b/Extension/src/LanguageServer/configurations.ts
@@ -73,6 +73,7 @@ export interface Configuration {
     compileCommands?: string;
     forcedInclude?: string[];
     configurationProvider?: string;
+    mergeConfigurations?: boolean;
     browse?: Browse;
     customConfigurationVariables?: {[key: string]: string};
 }