Add Alpine support (#480)

Author: johannespostler

Makefile

@@ -129,7 +129,7 @@ linux64: $(SQLITE_UNPACKED) jni-header
 	docker run $(DOCKER_RUN_OPTS) -ti -v $$PWD:/work xerial/centos5-linux-x86_64 bash -c 'make clean-native native OS_NAME=Linux OS_ARCH=x86_64'
 
 alpine-linux64: $(SQLITE_UNPACKED) jni-header
-	docker run $(DOCKER_RUN_OPTS) -ti -v $$PWD:/work xerial/alpine-linux-x86_64 bash -c 'make clean-native native OS_NAME=Linux OS_ARCH=x86_64'
+	docker run $(DOCKER_RUN_OPTS) -ti -v $$PWD:/work xerial/alpine-linux-x86_64 bash -c 'make clean-native native OS_NAME=Linux-Alpine OS_ARCH=x86_64'
 
 linux-arm: $(SQLITE_UNPACKED) jni-header
 	./docker/dockcross-armv5 -a $(DOCKER_RUN_OPTS) bash -c 'make clean-native native CROSS_PREFIX=/usr/xcc/armv5-unknown-linux-gnueabi/bin/armv5-unknown-linux-gnueabi- OS_NAME=Linux OS_ARCH=arm'

docker/Dockerfile.alpine-linux_x86_64

@@ -1,4 +1,4 @@
-FROM alpine
+FROM alpine:3.11
 MAINTAINER Taro L. Saito <leo@xerial.org>
 
 RUN apk --update add bash gcc make perl libc-dev

src/main/java/org/sqlite/util/OSInfo.java

@@ -113,6 +113,33 @@ public static boolean isAndroid() {
         return System.getProperty("java.runtime.name", "").toLowerCase().contains("android");
     }
 
+    public static boolean isAlpine() {
+        try {
+            Process p = Runtime.getRuntime().exec("cat /etc/os-release | grep ^ID");
+            p.waitFor();
+
+            InputStream in = p.getInputStream();
+            try {
+                int readLen = 0;
+                ByteArrayOutputStream b = new ByteArrayOutputStream();
+                byte[] buf = new byte[32];
+                while((readLen = in.read(buf, 0, buf.length)) >= 0) {
+                    b.write(buf, 0, readLen);
+                }
+                return b.toString().toLowerCase().contains("alpine");
+            }
+            finally {
+                if(in != null) {
+                    in.close();
+                }
+            }
+                
+        } catch (Throwable e) {
+            return false;
+        }
+        
+    }
+
     static String getHardwareName() {
         try {
             Process p = Runtime.getRuntime().exec("uname -m");
@@ -222,6 +249,9 @@ static String translateOSNameToFolderName(String osName) {
         else if (osName.contains("Mac") || osName.contains("Darwin")) {
             return "Mac";
         }
+        else if (isAlpine()) {
+            return "Linux-Alpine";
+        }
         else if (osName.contains("Linux")) {
             return "Linux";
         }