Add functions to jump to specific modules.

Usage:
...aosp/$ gomod libbase
...aosp/system/core/base$

Using in alias:
alias g=gomod
complete -F _complete-android-module-names g

...aosp/$ g libbase
...aosp/system/core/base$

Nothing in Android keeps an up to date index of all Android modules
and their locations between builds. However, there is a target
'module-info.json' which is used to contain some of that information.
This module can be updated using the command 'refreshmod' added
here, but it will also be updated during a normal Android build.

This also adds auto-complete for m.

Bug: N/A
Test: manual
Change-Id: I06b0b87c308b9fe2798dbc29225906cc30fe59fe

envsetup.sh

@@ -26,6 +26,9 @@ Invoke ". build/envsetup.sh" from your shell to add the following functions to y
 - sepgrep:    Greps on all local sepolicy files.
 - sgrep:      Greps on all local source files.
 - godir:      Go to the directory containing a file.
+- allmod:     List all modules.
+- gomod:      Go to the directory containing a module.
+- refreshmod: Refresh list of modules for allmod/gomod.
 
 Environment options:
 - SANITIZE_HOST: Set to 'true' to use ASAN for all host modules. Note that
@@ -359,6 +362,9 @@ function addcompletions()
         complete -C "bit --tab" bit
     fi
     complete -F _lunch lunch
+
+    complete -F _complete-android-module-names gomod
+    complete -F _complete-android-module-names m
 }
 
 function choosetype()
@@ -1463,6 +1469,77 @@ function godir () {
     \cd $T/$pathname
 }
 
+# Update module-info.json in out.
+function refreshmod() {
+    if [ ! "$ANDROID_PRODUCT_OUT" ]; then
+        echo "No ANDROID_PRODUCT_OUT. Try running 'lunch' first." >&2
+        return 1
+    fi
+
+    echo "Refreshing modules (building module-info.json). Log at $ANDROID_PRODUCT_OUT/module-info.json.build.log." >&2
+
+    # for the output of the next command
+    mkdir -p $ANDROID_PRODUCT_OUT || return 1
+
+    # Note, can't use absolute path because of the way make works.
+    m out/target/product/$(get_build_var TARGET_DEVICE)/module-info.json \
+        > $ANDROID_PRODUCT_OUT/module-info.json.build.log 2>&1
+}
+
+# List all modules for the current device, as cached in module-info.json. If any build change is
+# made and it should be reflected in the output, you should run 'refreshmod' first.
+function allmod() {
+    if [ ! "$ANDROID_PRODUCT_OUT" ]; then
+        echo "No ANDROID_PRODUCT_OUT. Try running 'lunch' first." >&2
+        return 1
+    fi
+
+    if [ ! -f "$ANDROID_PRODUCT_OUT/module-info.json" ]; then
+        echo "Could not find module-info.json. It will only be built once, and it can be updated with 'refreshmod'" >&2
+        refreshmod || return 1
+    fi
+
+    python -c "import json; print '\n'.join(sorted(json.load(open('$ANDROID_PRODUCT_OUT/module-info.json')).keys()))"
+}
+
+# Go to a specific module in the android tree, as cached in module-info.json. If any build change
+# is made, and it should be reflected in the output, you should run 'refreshmod' first.
+function gomod() {
+    if [ ! "$ANDROID_PRODUCT_OUT" ]; then
+        echo "No ANDROID_PRODUCT_OUT. Try running 'lunch' first." >&2
+        return 1
+    fi
+
+    if [[ $# -ne 1 ]]; then
+        echo "usage: gomod <module>" >&2
+        return 1
+    fi
+
+    if [ ! -f "$ANDROID_PRODUCT_OUT/module-info.json" ]; then
+        echo "Could not find module-info.json. It will only be built once, and it can be updated with 'refreshmod'" >&2
+        refreshmod || return 1
+    fi
+
+    local relpath=$(python -c "import json, os
+module = '$1'
+module_info = json.load(open('$ANDROID_PRODUCT_OUT/module-info.json'))
+if module not in module_info:
+    exit(1)
+print module_info[module]['path'][0]" 2>/dev/null)
+
+    if [ -z "$relpath" ]; then
+        echo "Could not find module '$1' (try 'refreshmod' if there have been build changes?)." >&2
+        return 1
+    else
+        cd $ANDROID_BUILD_TOP/$relpath
+    fi
+}
+
+function _complete-android-module-names() {
+    local word=${COMP_WORDS[COMP_CWORD]}
+    COMPREPLY=( $(allmod | grep -E "^$word") )
+}
+
 # Print colored exit condition
 function pez {
     "$@"