From af46e8c7e7eecce2b1caa9c175145e44f33f39ad Mon Sep 17 00:00:00 2001
From: Antti Kupila <akupila@gmail.com>
Date: Fri, 8 Feb 2019 10:46:08 +0100
Subject: [PATCH] detect wasm file type

---
 fixtures/sample.wasm    | Bin 0 -> 78 bytes
 match_test.go           |   1 +
 matchers/application.go |  20 ++++++++++++++++++++
 matchers/matchers.go    |   2 +-
 4 files changed, 22 insertions(+), 1 deletion(-)
 create mode 100644 fixtures/sample.wasm
 create mode 100644 matchers/application.go

diff --git a/fixtures/sample.wasm b/fixtures/sample.wasm
new file mode 100644
index 0000000000000000000000000000000000000000..a2e9ad6acbc70204dba743dd5064f0afab5a6e38
GIT binary patch
literal 78
zcmZQbEY4+QU|?Y6U`k-DXGmaRV3K5H&&(~zFDfbKh0v)f@oA-b$qWq4OpJ`|f{eVW
U6(DJtFe4WSBO8OGmH-1c0JS<1egFUf

literal 0
HcmV?d00001

diff --git a/match_test.go b/match_test.go
index f3e7efd..66dbb6d 100644
--- a/match_test.go
+++ b/match_test.go
@@ -47,6 +47,7 @@ func TestMatchFile(t *testing.T) {
 		{"pptx"},
 		{"xlsx"},
 		{"mov"},
+		{"wasm"},
 	}
 
 	for _, test := range cases {
diff --git a/matchers/application.go b/matchers/application.go
new file mode 100644
index 0000000..f482062
--- /dev/null
+++ b/matchers/application.go
@@ -0,0 +1,20 @@
+package matchers
+
+var (
+	TypeWasm = newType("wasm", "application/wasm")
+)
+
+var Application = Map{
+	TypeWasm: Wasm,
+}
+
+// Wasm detects a Web Assembly 1.0 filetype.
+func Wasm(buf []byte) bool {
+	// WASM has starts with `\0asm`, followed by the version.
+	// http://webassembly.github.io/spec/core/binary/modules.html#binary-magic
+	return len(buf) >= 8 &&
+		buf[0] == 0x00 && buf[1] == 0x61 &&
+		buf[2] == 0x73 && buf[3] == 0x6D &&
+		buf[4] == 0x01 && buf[5] == 0x00 &&
+		buf[6] == 0x00 && buf[7] == 0x00
+}
diff --git a/matchers/matchers.go b/matchers/matchers.go
index e9462df..20d74d0 100644
--- a/matchers/matchers.go
+++ b/matchers/matchers.go
@@ -47,5 +47,5 @@ func register(matchers ...Map) {
 func init() {
 	// Arguments order is intentional
 	// Archive files will be checked last due to prepend above in func NewMatcher
-	register(Archive, Document, Font, Audio, Video, Image)
+	register(Archive, Document, Font, Audio, Video, Image, Application)
 }