Fix issue 3402 . The initial suggestion of using readlink doesn't

Fix issue 3402 . The initial suggestion of using readlink doesn't
work on MacOS, so I went this slightly more obtuse solution, which
does work on MacOS and Linux.
Committed: https://code.google.com/p/dart/source/detail?r=13025

[ahe, 2012-09-28 03:47:30]

http://codereview.chromium.org/10985068/diff/1/utils/compiler/build_helper.dart
File utils/compiler/build_helper.dart (right):

http://codereview.chromium.org/10985068/diff/1/utils/compiler/build_helper.da...
utils/compiler/build_helper.dart:101: #!/bin/sh
This should be /bin/bash as the script relies on bash features.

http://codereview.chromium.org/10985068/diff/1/utils/compiler/build_helper.da...
utils/compiler/build_helper.dart:109: BIN_DIR=`cd "\$(dirname "\$0")"; pwd -P`
I've been reading up on the Bash manual
(http://www.gnu.org/software/bash/manual/bashref.html#Positional-Parameters)

As far as I can tell, there is no guarantee that $0 is an absolute path.
However, $_ is. So I prefer this version:

# Must be first command in this script.
ABS_SCRIPT_PATH="\$_"
BIN_DIR="\$(cd "\${ABS_SCRIPT_PATH%/*}" ; pwd -P)"

The advantage to ${ABS_SCRIPT_PATH%/*} over dirname ${ABS_SCRIPT_PATH} is that
it relies solely on bash built-in commands. This should make the script faster
(I'm actually seeing "dirname" showing up in the title of my Mac Terminal app
sometimes).

http://codereview.chromium.org/10985068/diff/1/utils/compiler/build_helper.da...
utils/compiler/build_helper.dart:119: exec \$BIN_DIR/dart$options
\$BIN_DIR/$path \$COLORS "\$@"
To handle spaces, this should be:

exec "\$BIN_DIR"/dart$options "\$BIN_DIR/$path" \$COLORS "\$@"

[dgrove, 2012-09-28 15:48:17]

Thanks Peter - I made these changes. I'll also update the pub script in a
separate CL.

http://codereview.chromium.org/10985068/diff/1/utils/compiler/build_helper.dart
File utils/compiler/build_helper.dart (right):

http://codereview.chromium.org/10985068/diff/1/utils/compiler/build_helper.da...
utils/compiler/build_helper.dart:101: #!/bin/sh
On 2012/09/28 03:47:30, ahe wrote:
> This should be /bin/bash as the script relies on bash features.

Done.

http://codereview.chromium.org/10985068/diff/1/utils/compiler/build_helper.da...
utils/compiler/build_helper.dart:109: BIN_DIR=`cd "\$(dirname "\$0")"; pwd -P`
On 2012/09/28 03:47:30, ahe wrote:
> I've been reading up on the Bash manual
> (http://www.gnu.org/software/bash/manual/bashref.html#Positional-Parameters)
> 
> As far as I can tell, there is no guarantee that $0 is an absolute path.
> However, $_ is. So I prefer this version:
> 
> # Must be first command in this script.
> ABS_SCRIPT_PATH="\$_"
> BIN_DIR="\$(cd "\${ABS_SCRIPT_PATH%/*}" ; pwd -P)"
> 
> The advantage to ${ABS_SCRIPT_PATH%/*} over dirname ${ABS_SCRIPT_PATH} is that
> it relies solely on bash built-in commands. This should make the script faster
> (I'm actually seeing "dirname" showing up in the title of my Mac Terminal app
> sometimes).

This seems like a good (but even uglier) alternative. I went ahead and switched
to this.

http://codereview.chromium.org/10985068/diff/1/utils/compiler/build_helper.da...
utils/compiler/build_helper.dart:119: exec \$BIN_DIR/dart$options
\$BIN_DIR/$path \$COLORS "\$@"
On 2012/09/28 03:47:30, ahe wrote:
> To handle spaces, this should be:
> 
> exec "\$BIN_DIR"/dart$options "\$BIN_DIR/$path" \$COLORS "\$@"

Done.

[ahe, 2012-09-28 15:55:03]

LGTM, thank you once again for taking care of these things that seem to fall
through the cracks.