jcache

#!/bin/bash

# Note: Only tested on OS X!
# For iOS you'll at least have to replace sed -E with -r, but maybe more.

set -e;

linkfrom() # src dst
{
    src="$1";
    base="$(basename "$2")";
    dst="$(dirname "$2")";
    srcParts=();
    dstParts=();
    while [ "$src" != "$(dirname "$src")" ]; do
        srcParts+=("$(basename "$src")");
        src="$(dirname "$src")";
    done;
    while [ "$dst" != "$(dirname "$dst")" ]; do
        dstParts+=("$(basename "$dst")");
        dst="$(dirname "$dst")";
    done;
    srcLen="${#srcParts[@]}";
    dstLen="${#dstParts[@]}";
    same=true;
    path='';
    for i in $(seq 1 "$((srcLen>dstLen?srcLen:dstLen))"); do
        s="$((srcLen-i))";
        d="$((dstLen-i))";
        if $same && [ "$s" -ge 0 ] && [ "$d" -ge 0 ] && [ "${srcParts[$s]}" == ${dstParts[$d]} ]; then
            continue;
        else
            same=false;
            if [ "$d" -ge 0 ]; then
                if [ -n "$path" ]; then
                    path="$path/${dstParts[$d]}";
                else
                    path="${dstParts[$d]}";
                fi;
            fi;
            if [ "$s" -ge 0 ]; then
                if [ -n "$path" ]; then
                    path="../$path";
                else
                    path='..';
                fi;
            fi;
        fi;
    done;
    if [ -n "$path" ]; then
        echo "$path/$base";
    else
        echo "$base";
    fi;
}

jtool='jtool';
if ! hash "$jtool"; then
    jtool="$(dirname "$0")/jtool";
    if ! [ -x "$jtool" ]; then
        echo "Couldn't find jtool executable in PATH or $(dirname "$0")";
        exit 1;
    fi;
fi;

file="$1";
if [ "$file" == '' ]; then
    echo "Usage:";
    echo "    $(basename "$0") dyld_shared_cache_arm*";
    exit 1;
fi;

"$jtool" -l "$file" | tail -n+2 | while read line; do
    dst="$(sed -E 's/^[[:space:]]*[0-9]+:[[:space:]]*[0-9a-f]+[[:space:]]+(.*)$/\1/' <<<"$line" | sed -E 's#//+#/#g')";
    key="fu_$(sed -E 's/^[[:space:]]*[0-9]+:[[:space:]]*([0-9a-f]+)[[:space:]]+.*$/\1/' <<<"$line")";
    mkdir -p "./$(dirname "$dst")";
    if [ -n "${!key}" ]; then
        if [ "$dst" != "${!key}" ]; then
            ln -s "$(linkfrom "$(dirname "$dst")" "${!key}")" "./$dst";
        fi;
        echo "$dst";
        echo "    => ${!key}";
    else
        src="$("$jtool" -e "$dst" "$file" 2>/dev/null | sed -E 's/^Extracting .* at 0x[0-9a-f]+ into (.*)$/\1/')";
        mv "$src" "./$dst";
        declare "$key=$dst";
        echo "$dst";
    fi;
done;