Add service interceptors

Author: JordonPhillips

smithy-docgen-core/src/main/java/software/amazon/smithy/docgen/core/generators/ServiceGenerator.java

@@ -9,11 +9,35 @@
 import software.amazon.smithy.codegen.core.directed.GenerateServiceDirective;
 import software.amazon.smithy.docgen.core.DocGenerationContext;
 import software.amazon.smithy.docgen.core.DocSettings;
+import software.amazon.smithy.docgen.core.sections.ServiceDetailsSection;
+import software.amazon.smithy.docgen.core.sections.ServiceSection;
 import software.amazon.smithy.model.shapes.ServiceShape;
 import software.amazon.smithy.utils.SmithyInternalApi;
 
 /**
- * Generates the top-level documentation for a service.
+ * Generates top-level documentation for the service.
+ *
+ * <p>The output of this can be customized in a number of ways. To add details to
+ * or re-write particular sections, register an interceptor with
+ * {@link software.amazon.smithy.docgen.core.DocIntegration#interceptors}. The following
+ * sections are guaranteed to be present:
+ *
+ * <ul>
+ *     <li>{@link ServiceDetailsSection}: Enables adding in additional details that are
+ *     inserted after the service's modeled documentation.
+ *     <li>{@link ServiceSection}: Enables re-writing or overwriting the entire page,
+ *     including changes made in other sections.
+ * </ul>
+ *
+ * <p>To change the intermediate format (e.g. from markdown to restructured text),
+ * a new {@link software.amazon.smithy.docgen.core.DocFormat} needs to be introduced
+ * via {@link software.amazon.smithy.docgen.core.DocIntegration#docFormats}.
+ *
+ * <p>To change the filename or title, implement
+ * {@link software.amazon.smithy.docgen.core.DocIntegration#decorateSymbolProvider}
+ * and modify the generated symbol's definition file. See
+ * {@link software.amazon.smithy.docgen.core.DocSymbolProvider} for details on other
+ * symbol-driven configuration options.
  */
 @SmithyInternalApi
 public final class ServiceGenerator implements Consumer<GenerateServiceDirective<DocGenerationContext, DocSettings>> {
@@ -24,10 +48,12 @@ public void accept(GenerateServiceDirective<DocGenerationContext, DocSettings> d
         var serviceSymbol = directive.symbolProvider().toSymbol(serviceShape);
 
         directive.context().writerDelegator().useShapeWriter(serviceShape, writer -> {
+            writer.pushState(new ServiceSection(directive.service(), directive.context()));
             writer.openHeading(serviceSymbol.getName());
             writer.writeShapeDocs(serviceShape);
-
+            writer.injectSection(new ServiceDetailsSection(directive.service(), directive.context()));
             writer.closeHeading();
+            writer.popState();
         });
     }
 

smithy-docgen-core/src/main/java/software/amazon/smithy/docgen/core/sections/ServiceDetailsSection.java

@@ -0,0 +1,23 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.docgen.core.sections;
+
+import software.amazon.smithy.docgen.core.DocGenerationContext;
+import software.amazon.smithy.model.shapes.ServiceShape;
+import software.amazon.smithy.utils.CodeSection;
+import software.amazon.smithy.utils.SmithyUnstableApi;
+
+/**
+ * Injects details after the model-defined service documentation.
+ *
+ * <p>To overwrite the whole service page, instead intercept the {@link ServiceSection}.
+ *
+ * @param service The service shape being generated.
+ * @param context The context used to generate documentation.
+ */
+@SmithyUnstableApi
+public record ServiceDetailsSection(ServiceShape service, DocGenerationContext context) implements CodeSection {
+}

smithy-docgen-core/src/main/java/software/amazon/smithy/docgen/core/sections/ServiceSection.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.docgen.core.sections;
+
+import software.amazon.smithy.docgen.core.DocGenerationContext;
+import software.amazon.smithy.model.shapes.ServiceShape;
+import software.amazon.smithy.utils.CodeSection;
+import software.amazon.smithy.utils.SmithyUnstableApi;
+
+/**
+ * Generates the entire Service detail page.
+ *
+ * <p>This enables overwriting the entire page. To simply add details after the
+ * service's trait-defined documentation, instead intercept
+ * {@link ServiceDetailsSection}.
+ *
+ * @param service The service shape being generated.
+ * @param context The context used to generate documentation.
+ */
+@SmithyUnstableApi
+public record ServiceSection(ServiceShape service, DocGenerationContext context) implements CodeSection {
+}