resolve most recursive type warnings in generator (ssm still has 2)

codegen/src/main.zig

@@ -69,6 +69,72 @@ fn generateServicesForFilePath(allocator: *std.mem.Allocator, comptime terminato
     defer file.close();
     return try generateServices(allocator, terminator, file, writer);
 }
+
+fn addReference(id: []const u8, map: *std.StringHashMap(u64)) !void {
+    const res = try map.getOrPut(id);
+    if (res.found_existing) {
+        res.value_ptr.* += 1;
+    } else {
+        res.value_ptr.* = 1;
+    }
+}
+fn countAllReferences(shape_ids: [][]const u8, shapes: std.StringHashMap(smithy.ShapeInfo), shape_references: *std.StringHashMap(u64), stack: *std.ArrayList([]const u8)) anyerror!void {
+    for (shape_ids) |id| {
+        try countReferences(shapes.get(id).?, shapes, shape_references, stack);
+    }
+}
+fn countTypeMembersReferences(type_members: []smithy.TypeMember, shapes: std.StringHashMap(smithy.ShapeInfo), shape_references: *std.StringHashMap(u64), stack: *std.ArrayList([]const u8)) anyerror!void {
+    for (type_members) |m| {
+        try countReferences(shapes.get(m.target).?, shapes, shape_references, stack);
+    }
+}
+
+fn countReferences(shape: smithy.ShapeInfo, shapes: std.StringHashMap(smithy.ShapeInfo), shape_references: *std.StringHashMap(u64), stack: *std.ArrayList([]const u8)) anyerror!void {
+    // Add ourselves as a reference, then we will continue down the tree
+    try addReference(shape.id, shape_references);
+    // Put ourselves on the stack. If we come back to ourselves, we want to end.
+    for (stack.items) |i| {
+        if (std.mem.eql(u8, shape.id, i))
+            return;
+    }
+    try stack.append(shape.id);
+    defer _ = stack.pop();
+    // Well, this is a fun read: https://awslabs.github.io/smithy/1.0/spec/core/model.html#recursive-shape-definitions
+    // Looks like recursion has special rules in the spec to accomodate Java.
+    // This is silly and we will ignore
+    switch (shape.shape) {
+        // We don't care about these primitives - they don't have children
+        .blob,
+        .boolean,
+        .string,
+        .byte,
+        .short,
+        .integer,
+        .long,
+        .float,
+        .double,
+        .bigInteger,
+        .bigDecimal,
+        .timestamp,
+        => {},
+        .document, .member, .resource => {}, // less sure about these?
+        .list => |i| try countReferences(shapes.get(i.member_target).?, shapes, shape_references, stack),
+        .set => |i| try countReferences(shapes.get(i.member_target).?, shapes, shape_references, stack),
+        .map => |i| {
+            try countReferences(shapes.get(i.key).?, shapes, shape_references, stack);
+            try countReferences(shapes.get(i.value).?, shapes, shape_references, stack);
+        },
+        .structure => |m| try countTypeMembersReferences(m.members, shapes, shape_references, stack),
+        .uniontype => |m| try countTypeMembersReferences(m.members, shapes, shape_references, stack),
+        .service => |i| try countAllReferences(i.operations, shapes, shape_references, stack),
+        .operation => |op| {
+            if (op.input) |i| try countReferences(shapes.get(i).?, shapes, shape_references, stack);
+            if (op.output) |i| try countReferences(shapes.get(i).?, shapes, shape_references, stack);
+            if (op.errors) |i| try countAllReferences(i, shapes, shape_references, stack);
+        },
+    }
+}
+
 fn generateServices(allocator: *std.mem.Allocator, comptime _: []const u8, file: std.fs.File, writer: anytype) ![][]const u8 {
     const json = try file.readToEndAlloc(allocator, 1024 * 1024 * 1024);
     defer allocator.free(json);
@@ -85,8 +151,29 @@ fn generateServices(allocator: *std.mem.Allocator, comptime _: []const u8, file:
             else => {},
         }
     }
+    // At this point we want to generate a graph of shapes, starting
+    // services -> operations -> other shapes. This will allow us to get
+    // a reference count in case there are recursive data structures
+    var shape_references = std.StringHashMap(u64).init(allocator);
+    defer shape_references.deinit();
+    var stack = std.ArrayList([]const u8).init(allocator);
+    defer stack.deinit();
+    for (services.items) |service|
+        try countReferences(service, shapes, &shape_references, &stack);
+
     var constant_names = std.ArrayList([]const u8).init(allocator);
     defer constant_names.deinit();
+    var unresolved = std.ArrayList(smithy.ShapeInfo).init(allocator);
+    defer unresolved.deinit();
+    var generated = std.StringHashMap(void).init(allocator);
+    defer generated.deinit();
+
+    var state = FileGenerationState{
+        .shape_references = shape_references,
+        .additional_types_to_generate = &unresolved,
+        .additional_types_generated = &generated,
+        .shapes = shapes,
+    };
     for (services.items) |service| {
         var sdk_id: []const u8 = undefined;
         var version: []const u8 = service.shape.service.version;
@@ -136,10 +223,33 @@ fn generateServices(allocator: *std.mem.Allocator, comptime _: []const u8, file:
 
         // Operations
         for (service.shape.service.operations) |op|
-            try generateOperation(allocator, shapes.get(op).?, shapes, writer);
+            try generateOperation(allocator, shapes.get(op).?, state, writer);
     }
+    try generateAdditionalTypes(allocator, state, writer);
     return constant_names.toOwnedSlice();
 }
+
+fn generateAdditionalTypes(allocator: *std.mem.Allocator, file_state: FileGenerationState, writer: anytype) !void {
+    // More types may be added during processing
+    while (file_state.additional_types_to_generate.popOrNull()) |t| {
+        if (file_state.additional_types_generated.getEntry(t.name) != null) continue;
+        // std.log.info("\t\t{s}", .{t.name});
+        var type_stack = std.ArrayList(*const smithy.ShapeInfo).init(allocator);
+        defer type_stack.deinit();
+        const state = GenerationState{
+            .type_stack = &type_stack,
+            .file_state = file_state,
+            .allocator = allocator,
+            .indent_level = 0,
+        };
+        const type_name = avoidReserved(t.name);
+        try writer.print("\npub const {s} = ", .{type_name});
+        try file_state.additional_types_generated.putNoClobber(t.name, {});
+        _ = try generateTypeFor(t.id, writer, state, true);
+        _ = try writer.write(";\n");
+    }
+}
+
 fn constantName(allocator: *std.mem.Allocator, id: []const u8) ![]const u8 {
     // There are some ids that don't follow consistent rules, so we'll
     // look for the exceptions and, if not found, revert to the snake case
@@ -161,19 +271,25 @@ fn constantName(allocator: *std.mem.Allocator, id: []const u8) ![]const u8 {
     return try snake.fromPascalCase(allocator, id);
 }
 
+const FileGenerationState = struct {
+    shapes: std.StringHashMap(smithy.ShapeInfo),
+    shape_references: std.StringHashMap(u64),
+    additional_types_to_generate: *std.ArrayList(smithy.ShapeInfo),
+    additional_types_generated: *std.StringHashMap(void),
+};
 const GenerationState = struct {
     type_stack: *std.ArrayList(*const smithy.ShapeInfo),
+    file_state: FileGenerationState,
     // we will need some sort of "type decls needed" for recursive structures
     allocator: *std.mem.Allocator,
     indent_level: u64,
-    all_required: bool,
 };
 
 fn outputIndent(state: GenerationState, writer: anytype) !void {
     const n_chars = 4 * state.indent_level;
     try writer.writeByteNTimes(' ', n_chars);
 }
-fn generateOperation(allocator: *std.mem.Allocator, operation: smithy.ShapeInfo, shapes: std.StringHashMap(smithy.ShapeInfo), writer: anytype) !void {
+fn generateOperation(allocator: *std.mem.Allocator, operation: smithy.ShapeInfo, file_state: FileGenerationState, writer: anytype) !void {
     const snake_case_name = try snake.fromPascalCase(allocator, operation.name);
     defer allocator.free(snake_case_name);
 
@@ -181,9 +297,9 @@ fn generateOperation(allocator: *std.mem.Allocator, operation: smithy.ShapeInfo,
     defer type_stack.deinit();
     const state = GenerationState{
         .type_stack = &type_stack,
+        .file_state = file_state,
         .allocator = allocator,
         .indent_level = 1,
-        .all_required = false,
     };
     var child_state = state;
     child_state.indent_level += 1;
@@ -211,7 +327,7 @@ fn generateOperation(allocator: *std.mem.Allocator, operation: smithy.ShapeInfo,
     try outputIndent(state, writer);
     _ = try writer.write("Request: type = ");
     if (operation.shape.operation.input) |member| {
-        if (try generateTypeFor(member, shapes, writer, state, false)) unreachable; // we expect only structs here
+        if (try generateTypeFor(member, writer, state, false)) unreachable; // we expect only structs here
         _ = try writer.write("\n");
         try generateMetadataFunction(operation_name, state, writer);
     } else {
@@ -222,7 +338,7 @@ fn generateOperation(allocator: *std.mem.Allocator, operation: smithy.ShapeInfo,
     try outputIndent(state, writer);
     _ = try writer.write("Response: type = ");
     if (operation.shape.operation.output) |member| {
-        if (try generateTypeFor(member, shapes, writer, state, true)) unreachable; // we expect only structs here
+        if (try generateTypeFor(member, writer, state, true)) unreachable; // we expect only structs here
     } else _ = try writer.write("struct {}"); // we want to maintain consistency with other ops
     _ = try writer.write(",\n");
 
@@ -230,7 +346,7 @@ fn generateOperation(allocator: *std.mem.Allocator, operation: smithy.ShapeInfo,
         try outputIndent(state, writer);
         _ = try writer.write("ServiceError: type = error{\n");
         for (errors) |err| {
-            const err_name = getErrorName(shapes.get(err).?.name); // need to remove "exception"
+            const err_name = getErrorName(file_state.shapes.get(err).?.name); // need to remove "exception"
             try outputIndent(child_state, writer);
             try writer.print("{s},\n", .{err_name});
         }
@@ -276,16 +392,42 @@ fn endsWith(item: []const u8, str: []const u8) bool {
     if (str.len < item.len) return false;
     return std.mem.eql(u8, item, str[str.len - item.len ..]);
 }
-/// return type is anyerror!void as this is a recursive function, so the compiler cannot properly infer error types
-fn generateTypeFor(shape_id: []const u8, shapes: std.StringHashMap(smithy.ShapeInfo), writer: anytype, state: GenerationState, end_structure: bool) anyerror!bool {
+
+fn reuseCommonType(shape: smithy.ShapeInfo, writer: anytype, state: GenerationState) !bool {
+    // We want to return if we're at the top level of the stack. There are three
+    // reasons for this:
+    // 1. For operations, we have a request that includes a metadata function
+    //    to enable aws.zig eventually to find the action based on a request.
+    //    This could be considered a hack and maybe we should remove that
+    //    caller convenience ability.
+    // 2. Given the state of zig compiler tooling, "intellisense" or whatever
+    //    we're calling it these days, isn't real mature, so we end up looking
+    //    at the models quite a bit. Leaving the top level alone here reduces
+    //    the need for users to hop around too much looking at types as they
+    //    can at least see the top level.
+    // 3. When we come through at the end, we want to make sure we're writing
+    //    something or we'll have an infinite loop!
+    if (state.type_stack.items.len == 1) return false;
     var rc = false;
-    if (shapes.get(shape_id) == null) {
-        std.debug.print("Shape ID not found. This is most likely a bug. Shape ID: {s}\n", .{shape_id});
-        return error.InvalidType;
+    if (state.file_state.shape_references.get(shape.id)) |r| {
+        if (r > 1 and (shape.shape == .structure or shape.shape == .uniontype)) {
+            rc = true;
+            _ = try writer.write(avoidReserved(shape.name)); // This can't possibly be this easy...
+            if (state.file_state.additional_types_generated.getEntry(shape.name) == null)
+                try state.file_state.additional_types_to_generate.append(shape);
+        }
     }
+    return rc;
+}
+/// return type is anyerror!void as this is a recursive function, so the compiler cannot properly infer error types
+fn generateTypeFor(shape_id: []const u8, writer: anytype, state: GenerationState, end_structure: bool) anyerror!bool {
+    var rc = false;
 
     // We assume it must exist
-    const shape_info = shapes.get(shape_id).?;
+    const shape_info = state.file_state.shapes.get(shape_id) orelse {
+        std.debug.print("Shape ID not found. This is most likely a bug. Shape ID: {s}\n", .{shape_id});
+        return error.InvalidType;
+    };
     const shape = shape_info.shape;
     // Check for ourselves up the stack
     var self_occurences: u8 = 0;
@@ -324,30 +466,34 @@ fn generateTypeFor(shape_id: []const u8, shapes: std.StringHashMap(smithy.ShapeI
     defer _ = state.type_stack.pop();
     switch (shape) {
         .structure => {
-            try generateComplexTypeFor(shape_id, shape.structure.members, "struct", shapes, writer, state);
-            if (end_structure) {
+            if (!try reuseCommonType(shape_info, writer, state)) {
+                try generateComplexTypeFor(shape_id, shape.structure.members, "struct", writer, state);
+                if (end_structure) {
+                    // epilog
+                    try outputIndent(state, writer);
+                    _ = try writer.write("}");
+                }
+            }
+        },
+        .uniontype => {
+            if (!try reuseCommonType(shape_info, writer, state)) {
+                try generateComplexTypeFor(shape_id, shape.uniontype.members, "union", writer, state);
                 // epilog
                 try outputIndent(state, writer);
                 _ = try writer.write("}");
             }
         },
-        .uniontype => {
-            try generateComplexTypeFor(shape_id, shape.uniontype.members, "union", shapes, writer, state);
-            // epilog
-            try outputIndent(state, writer);
-            _ = try writer.write("}");
-        },
         .string => |s| try generateSimpleTypeFor(s, "[]const u8", writer),
         .integer => |s| try generateSimpleTypeFor(s, "i64", writer),
         .list => {
             _ = try writer.write("[]");
             // The serializer will have to deal with the idea we might be an array
-            return try generateTypeFor(shape.list.member_target, shapes, writer, state, true);
+            return try generateTypeFor(shape.list.member_target, writer, state, true);
         },
         .set => {
             _ = try writer.write("[]");
             // The serializer will have to deal with the idea we might be an array
-            return try generateTypeFor(shape.set.member_target, shapes, writer, state, true);
+            return try generateTypeFor(shape.set.member_target, writer, state, true);
         },
         .timestamp => |s| try generateSimpleTypeFor(s, "i64", writer),
         .blob => |s| try generateSimpleTypeFor(s, "[]const u8", writer),
@@ -364,14 +510,14 @@ fn generateTypeFor(shape_id: []const u8, shapes: std.StringHashMap(smithy.ShapeI
             try writeOptional(shape.map.traits, writer, null);
             var sub_maps = std.ArrayList([]const u8).init(state.allocator);
             defer sub_maps.deinit();
-            if (try generateTypeFor(shape.map.key, shapes, writer, child_state, true))
+            if (try generateTypeFor(shape.map.key, writer, child_state, true))
                 try sub_maps.append("key");
             try writeOptional(shape.map.traits, writer, " = null");
             _ = try writer.write(",\n");
             try outputIndent(child_state, writer);
             _ = try writer.write("value: ");
             try writeOptional(shape.map.traits, writer, null);
-            if (try generateTypeFor(shape.map.value, shapes, writer, child_state, true))
+            if (try generateTypeFor(shape.map.value, writer, child_state, true))
                 try sub_maps.append("value");
             try writeOptional(shape.map.traits, writer, " = null");
             _ = try writer.write(",\n");
@@ -396,7 +542,7 @@ fn generateTypeFor(shape_id: []const u8, shapes: std.StringHashMap(smithy.ShapeI
 fn generateSimpleTypeFor(_: anytype, type_name: []const u8, writer: anytype) !void {
     _ = try writer.write(type_name); // This had required stuff but the problem was elsewhere. Better to leave as function just in case
 }
-fn generateComplexTypeFor(shape_id: []const u8, members: []smithy.TypeMember, type_type_name: []const u8, shapes: std.StringHashMap(smithy.ShapeInfo), writer: anytype, state: GenerationState) anyerror!void {
+fn generateComplexTypeFor(shape_id: []const u8, members: []smithy.TypeMember, type_type_name: []const u8, writer: anytype, state: GenerationState) anyerror!void {
     _ = shape_id;
     const Mapping = struct { snake: []const u8, json: []const u8 };
     var json_field_name_mappings = try std.ArrayList(Mapping).initCapacity(state.allocator, members.len);
@@ -459,7 +605,7 @@ fn generateComplexTypeFor(shape_id: []const u8, members: []smithy.TypeMember, ty
         const member_name = avoidReserved(snake_case_member);
         try writer.print("{s}: ", .{member_name});
         try writeOptional(member.traits, writer, null);
-        if (try generateTypeFor(member.target, shapes, writer, child_state, true))
+        if (try generateTypeFor(member.target, writer, child_state, true))
             try map_fields.append(try std.fmt.allocPrint(state.allocator, "{s}", .{member_name}));
 
         if (!std.mem.eql(u8, "union", type_type_name))