画像のファイルヘッダを見てmimeTypeを修正する

.idea/misc.xml

@@ -29,7 +29,7 @@
       </value>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" default="true" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">

app/build.gradle

@@ -11,8 +11,8 @@ android {
         targetSdkVersion target_sdk_version
         minSdkVersion min_sdk_version
 
-        versionCode 285
-        versionName "2.8.5"
+        versionCode 286
+        versionName "2.8.6"
         applicationId "jp.juggler.subwaytooter"
         testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
 

app/src/main/java/jp/juggler/subwaytooter/ActPost.kt

@@ -4,6 +4,7 @@ import android.Manifest
 import android.annotation.SuppressLint
 import android.app.Activity
 import android.app.Dialog
+import android.content.ContentResolver
 import android.content.ContentValues
 import android.content.Intent
 import android.content.SharedPreferences
@@ -101,6 +102,29 @@ class ActPost : AppCompatActivity(), View.OnClickListener, PostAttachment.Callba
 			add("video/quicktime")
 		}
 		
+		private val imageHeaderList = arrayOf(
+			Pair("image/jpeg",intArrayOf(0xff,0xd8,0xff,0xe0).toByteArray()),
+			Pair("image/png",intArrayOf(0x89 ,0x50 ,0x4E ,0x47 ,0x0D ,0x0A ,0x1A ,0x0A).toByteArray()),
+			Pair("image/gif", charArrayOf('G' ,'I' ,'F').toByteArray())
+		)
+		
+		private fun checkImageHeaderList(contentResolver:ContentResolver, uri : Uri) : String? {
+			try{
+				contentResolver.openInputStream(uri)?.use{ inStream ->
+					val data = ByteArray(32)
+					val nRead = inStream.read(data,0,data.size)
+					for( pair in imageHeaderList ){
+						val type = pair.first
+						val header = pair.second
+						if( nRead >= header.size && data.startWith(header) ) return type
+					}
+				}
+			}catch(ex:Throwable){
+				log.e(ex,"checkImageHeaderList failed.")
+			}
+			return null
+		}
+		
 		//	private void performCameraVideo(){
 		//
 		//		try{
@@ -1481,8 +1505,17 @@ class ActPost : AppCompatActivity(), View.OnClickListener, PostAttachment.Callba
 	
 	private fun getMimeType(uri : Uri, mimeTypeArg : String?) : String? {
 		
+		// image/j()pg だの image/j(e)pg だの、mime type を誤記するアプリがあまりに多い
+		// クレームで消耗するのを減らすためにファイルヘッダを確認する
+		if(mimeTypeArg == null || mimeTypeArg.startsWith("image/")){
+			val sv = checkImageHeaderList(contentResolver,uri)
+			if( sv != null) return sv
+		}
+
 		// 既に引数で与えられてる
-		if(mimeTypeArg?.isNotEmpty() == true) return mimeTypeArg
+		if(mimeTypeArg?.isNotEmpty() == true){
+			return mimeTypeArg
+		}
 		
 		// ContentResolverに尋ねる
 		var sv = contentResolver.getType(uri)
@@ -1495,6 +1528,8 @@ class ActPost : AppCompatActivity(), View.OnClickListener, PostAttachment.Callba
 		return null
 	}
 	
+
+	
 	@SuppressLint("StaticFieldLeak")
 	private fun addAttachment(
 		uri : Uri,

app/src/main/java/jp/juggler/subwaytooter/util/Utils.kt

@@ -351,6 +351,40 @@ fun ByteArray.digestSHA256() : ByteArray {
 	return digest.digest(this)
 }
 
+fun ByteArray.startWith(
+	key:ByteArray,
+	thisOffset :Int =0,
+	keyOffset:Int=0,
+	length:Int = key.size-keyOffset
+):Boolean{
+	if( this.size -thisOffset >= length && key.size -keyOffset >=length ){
+		for( i in 0 until length ){
+			if( this[i+thisOffset] != key[i+keyOffset]) return false
+		}
+		return true
+	}
+	return false
+}
+
+// 各要素の下位8ビットを使ってバイト配列を作る
+fun IntArray.toByteArray():ByteArray{
+	val dst = ByteArray(this.size)
+	for(i in 0 until this.size){
+		dst[i] = this[i].toByte()
+	}
+	return dst
+}
+
+// 各要素の下位8ビットを使ってバイト配列を作る
+fun CharArray.toByteArray():ByteArray{
+	val dst = ByteArray(this.size)
+	for(i in 0 until this.size){
+		dst[i] = this[i].toByte()
+	}
+	return dst
+}
+
+
 //// MD5ハッシュの作成
 //@Suppress("unused")
 //fun String.digestMD5() : String {

build.gradle

@@ -1,6 +1,6 @@
 buildscript {
 
-    ext.kotlin_version = '1.2.61'
+    ext.kotlin_version = '1.2.70'
     ext.kotlin_coroutines_version = '0.25.3'
     ext.anko_version='0.10.5'
     ext.asl_version='27.1.1'