Use `xz` tarballs if available

Saves us ~25% bandwidth while downloading the payload. This only applies
to hosts that has the `xz` binary and attempts to use iojs 2.3.2 or newer
(this includes nodejs 4.0+ as well). Older targets are unaffected.

nvm.sh

@@ -999,16 +999,24 @@ nvm_install_merged_node_binary() {
   local url
   local sum
   local NODE_PREFIX
+  local compression
+  compression="gz"
+  local tar_compression_flag
+  tar_compression_flag="x"
+  if nvm_supports_xz "$VERSION"; then
+    compression="xz"
+    tar_compression_flag="J"
+  fi
   NODE_PREFIX="$(nvm_node_prefix)"
 
   if [ -n "$NVM_OS" ]; then
     t="$VERSION-$NVM_OS-$(nvm_get_arch)"
-    url="$MIRROR/$VERSION/$NODE_PREFIX-${t}.tar.gz"
-    sum="$(nvm_download -L -s $MIRROR/$VERSION/SHASUMS256.txt -o - | command grep $NODE_PREFIX-${t}.tar.gz | command awk '{print $1}')"
+    url="$MIRROR/$VERSION/$NODE_PREFIX-${t}.tar.${compression}"
+    sum="$(nvm_download -L -s $MIRROR/$VERSION/SHASUMS256.txt -o - | command grep $NODE_PREFIX-${t}.tar.${compression} | command awk '{print $1}')"
     local tmpdir
     tmpdir="$NVM_DIR/bin/node-${t}"
     local tmptarball
-    tmptarball="$tmpdir/node-${t}.tar.gz"
+    tmptarball="$tmpdir/node-${t}.tar.${compression}"
     local NVM_INSTALL_ERRORED
     command mkdir -p "$tmpdir" && \
       echo "Downloading $url..." && \
@@ -1022,7 +1030,7 @@ nvm_install_merged_node_binary() {
       [ "$NVM_INSTALL_ERRORED" != true ] && \
       echo "WARNING: checksums are currently disabled for node.js v4.0 and later" >&2 && \
       # nvm_checksum "$tmptarball" $sum && \
-      command tar -xzf "$tmptarball" -C "$tmpdir" --strip-components 1 && \
+      command tar -x${tar_compression_flag}f "$tmptarball" -C "$tmpdir" --strip-components 1 && \
       command rm -f "$tmptarball" && \
       command mkdir -p "$VERSION_PATH" && \
       command mv "$tmpdir"/* "$VERSION_PATH"
@@ -1066,16 +1074,24 @@ nvm_install_iojs_binary() {
   local t
   local url
   local sum
+  local compression
+  compression="gz"
+  local tar_compression_flag
+  tar_compression_flag="x"
+  if nvm_supports_xz "$VERSION"; then
+    compression="xz"
+    tar_compression_flag="J"
+  fi
 
   if [ -n "$NVM_OS" ]; then
     if nvm_binary_available "$VERSION"; then
       t="$VERSION-$NVM_OS-$(nvm_get_arch)"
-      url="$MIRROR/$VERSION/$(nvm_iojs_prefix)-${t}.tar.gz"
-      sum="$(nvm_download -L -s $MIRROR/$VERSION/SHASUMS256.txt -o - | command grep $(nvm_iojs_prefix)-${t}.tar.gz | command awk '{print $1}')"
+      url="$MIRROR/$VERSION/$(nvm_iojs_prefix)-${t}.tar.${compression}"
+      sum="$(nvm_download -L -s $MIRROR/$VERSION/SHASUMS256.txt -o - | command grep $(nvm_iojs_prefix)-${t}.tar.${compression} | command awk '{print $1}')"
       local tmpdir
       tmpdir="$NVM_DIR/bin/iojs-${t}"
       local tmptarball
-      tmptarball="$tmpdir/iojs-${t}.tar.gz"
+      tmptarball="$tmpdir/iojs-${t}.tar.${compression}"
       local NVM_INSTALL_ERRORED
       command mkdir -p "$tmpdir" && \
         echo "Downloading $url..." && \
@@ -1089,7 +1105,7 @@ nvm_install_iojs_binary() {
         [ "$NVM_INSTALL_ERRORED" != true ] && \
         echo "WARNING: checksums are currently disabled for io.js" >&2 && \
         # nvm_checksum "$tmptarball" $sum && \
-        command tar -xzf "$tmptarball" -C "$tmpdir" --strip-components 1 && \
+        command tar -x${tar_compression_flag}f "$tmptarball" -C "$tmpdir" --strip-components 1 && \
         command rm -f "$tmptarball" && \
         command mkdir -p "$VERSION_PATH" && \
         command mv "$tmpdir"/* "$VERSION_PATH"
@@ -1662,9 +1678,9 @@ nvm() {
       fi
       # Delete all files related to target version.
       command rm -rf "$NVM_DIR/src/$NVM_PREFIX-$VERSION" \
-             "$NVM_DIR/src/$NVM_PREFIX-$VERSION.tar.gz" \
+             "$NVM_DIR/src/$NVM_PREFIX-$VERSION.tar.*" \
              "$NVM_DIR/bin/$NVM_PREFIX-${t}" \
-             "$NVM_DIR/bin/$NVM_PREFIX-${t}.tar.gz" \
+             "$NVM_DIR/bin/$NVM_PREFIX-${t}.tar.*" \
              "$VERSION_PATH" 2>/dev/null
       echo "$NVM_SUCCESS_MSG"
 
@@ -2200,7 +2216,7 @@ $NVM_LS_REMOTE_POST_MERGED_OUTPUT" | command grep -v "N/A" | command sed '/^$/d'
         nvm_print_npm_version nvm_npm_global_modules \
         nvm_has_system_node nvm_has_system_iojs \
         nvm_download nvm_get_latest nvm_has nvm_get_latest \
-        nvm_supports_source_options > /dev/null 2>&1
+        nvm_supports_source_options nvm_supports_xz > /dev/null 2>&1
       unset RC_VERSION NVM_NODEJS_ORG_MIRROR NVM_DIR NVM_CD_FLAGS > /dev/null 2>&1
     ;;
     * )
@@ -2214,6 +2230,11 @@ nvm_supports_source_options() {
   [ "_$(echo 'echo $1' | . /dev/stdin yes 2> /dev/null)" = "_yes" ]
 }
 
+nvm_supports_xz() {
+  command which xz 2>&1 >/dev/null && \
+    nvm_version_greater_than_or_equal_to "$1" "2.3.2" 
+}
+
 NVM_VERSION="$(nvm_alias default 2>/dev/null || echo)"
 if nvm_supports_source_options && [ "_$1" = "_--install" ]; then
   if [ -n "$NVM_VERSION" ]; then

test/fast/Unit tests/nvm_supports_xz

@@ -0,0 +1,36 @@
+#!/bin/sh
+
+die () { echo $@ ; exit 1; }
+
+. ../../../nvm.sh
+
+OLDPATH=$PATH
+TEST_PATH=../../xz-test
+
+mkdir $TEST_PATH
+touch ../../xz-test/xz
+chmod +x ../../xz-test/xz
+
+export PATH=$TEST_PATH:$PATH
+
+$(nvm_supports_xz "v2.3.2") || \
+  die "expected 'nvm_supports_xz v2.3.2' to exit with 0"
+
+$(nvm_supports_xz "v0.12.7") && \
+  die "expected 'nvm_supports_xz v0.12.7' to exit with 1"
+
+
+# set up for a failure by having a minimal toolset available
+# but remove xz
+ln -s /usr/bin/which $TEST_PATH/which
+ln -s /usr/bin/command $TEST_PATH/command
+ln -s /usr/bin/awk $TEST_PATH/awk
+ln -s $(which rm) $TEST_PATH/rm
+
+export PATH=$TEST_PATH
+rm $TEST_PATH/xz
+
+$(nvm_supports_xz "v2.3.2") && \
+  die "expected 'nvm_supports_xz v2.3.2' with a missing xz binary to exit with 1"
+
+export PATH=$OLDPATH

test/fast/teardown

@@ -6,5 +6,5 @@
 
   type setopt >/dev/null 2>&1 && setopt NULL_GLOB
   type shopt >/dev/null 2>&1 && shopt -s nullglob
-  rm -fR v* src alias
+  rm -fR v* src alias test/test-xz
 )