From 8c379296cad4b307897d1c9e6d73d40fa66c18ed Mon Sep 17 00:00:00 2001
From: Ilya Puchka <ilyapuchka@gmail.com>
Date: Sat, 30 Dec 2017 03:02:18 +0100
Subject: [PATCH] Cache rendered blocks content to reuse them in further calls

---
 Sources/Stencil/Context.swift                 | 15 +++++++++++++++
 Sources/Stencil/Inheritance.swift             |  4 +++-
 Tests/StencilTests/InheritanceSpec.swift      | 18 ++++++++++++++++++
 Tests/StencilTests/fixtures/base-repeat.html  |  5 +++++
 Tests/StencilTests/fixtures/child-repeat.html |  3 +++
 5 files changed, 44 insertions(+), 1 deletion(-)
 create mode 100644 Tests/StencilTests/fixtures/base-repeat.html
 create mode 100644 Tests/StencilTests/fixtures/child-repeat.html

diff --git a/Sources/Stencil/Context.swift b/Sources/Stencil/Context.swift
index 1858694..b4a0b2a 100644
--- a/Sources/Stencil/Context.swift
+++ b/Sources/Stencil/Context.swift
@@ -85,4 +85,19 @@ public class Context {
 
     return accumulator
   }
+
+  /// Cache result of block by its name in the context top-level, so that it can be later rendered
+  /// via `{{ block.name }}`
+  ///
+  /// - Parameters:
+  ///   - name: The name of the stored block
+  ///   - content: The block's rendered content
+  public func cacheBlock(_ name: String, content: String) {
+    if var block = dictionaries.first?["block"] as? [String: String] {
+      block[name] = content
+      dictionaries[0]["block"] = block
+    } else {
+      dictionaries.insert(["block": [name: content]], at: 0)
+    }
+  }
 }
diff --git a/Sources/Stencil/Inheritance.swift b/Sources/Stencil/Inheritance.swift
index 1f75e9b..971ded1 100644
--- a/Sources/Stencil/Inheritance.swift
+++ b/Sources/Stencil/Inheritance.swift
@@ -151,6 +151,8 @@ class BlockNode: NodeType {
       }
     }
 
-    return try renderNodes(nodes, context)
+    let result = try renderNodes(nodes, context)
+    context.cacheBlock(name, content: result)
+    return result
   }
 }
diff --git a/Tests/StencilTests/InheritanceSpec.swift b/Tests/StencilTests/InheritanceSpec.swift
index e16d83e..117b605 100644
--- a/Tests/StencilTests/InheritanceSpec.swift
+++ b/Tests/StencilTests/InheritanceSpec.swift
@@ -52,4 +52,22 @@ final class InheritanceTests: XCTestCase {
       """
     }
   }
+
+  func testInheritanceCache() {
+    it("can call block twice") {
+      let template: Template = "{% block repeat %}Block{% endblock %}{{ block.repeat }}"
+      try expect(try template.render()) == "BlockBlock"
+    }
+
+    it("renders child content when calling block twice in base template") {
+      let template = try self.environment.loadTemplate(name: "child-repeat.html")
+      try expect(try template.render()) == """
+      Super_Header Child_Header
+      Child_Body
+      Repeat
+      Super_Header Child_Header
+      Child_Body
+      """
+    }
+  }
 }
diff --git a/Tests/StencilTests/fixtures/base-repeat.html b/Tests/StencilTests/fixtures/base-repeat.html
new file mode 100644
index 0000000..310b3b1
--- /dev/null
+++ b/Tests/StencilTests/fixtures/base-repeat.html
@@ -0,0 +1,5 @@
+{% block header %}Header{% endblock %}
+{% block body %}Body{% endblock %}
+Repeat
+{{ block.header }}
+{{ block.body }}
\ No newline at end of file
diff --git a/Tests/StencilTests/fixtures/child-repeat.html b/Tests/StencilTests/fixtures/child-repeat.html
new file mode 100644
index 0000000..088b2b4
--- /dev/null
+++ b/Tests/StencilTests/fixtures/child-repeat.html
@@ -0,0 +1,3 @@
+{% extends "base-repeat.html" %}
+{% block header %}Super_{{ block.super }} Child_Header{% endblock %}
+{% block body %}Child_Body{% endblock %}