/thirdparty/breakpad/third_party/linux/include/gflags/gflags_completions.h
http://github.com/tomahawk-player/tomahawk · C++ Header · 121 lines · 6 code · 8 blank · 107 comment · 0 complexity · 2f48d065f09ed527478ef10054dce0dd MD5 · raw file
- // Copyright (c) 2008, Google Inc.
- // All rights reserved.
- //
- // Redistribution and use in source and binary forms, with or without
- // modification, are permitted provided that the following conditions are
- // met:
- //
- // * Redistributions of source code must retain the above copyright
- // notice, this list of conditions and the following disclaimer.
- // * Redistributions in binary form must reproduce the above
- // copyright notice, this list of conditions and the following disclaimer
- // in the documentation and/or other materials provided with the
- // distribution.
- // * Neither the name of Google Inc. nor the names of its
- // contributors may be used to endorse or promote products derived from
- // this software without specific prior written permission.
- //
- // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- //
- // ---
- // Author: Dave Nicponski
- //
- // Implement helpful bash-style command line flag completions
- //
- // ** Functional API:
- // HandleCommandLineCompletions() should be called early during
- // program startup, but after command line flag code has been
- // initialized, such as the beginning of HandleCommandLineHelpFlags().
- // It checks the value of the flag --tab_completion_word. If this
- // flag is empty, nothing happens here. If it contains a string,
- // however, then HandleCommandLineCompletions() will hijack the
- // process, attempting to identify the intention behind this
- // completion. Regardless of the outcome of this deduction, the
- // process will be terminated, similar to --helpshort flag
- // handling.
- //
- // ** Overview of Bash completions:
- // Bash can be told to programatically determine completions for the
- // current 'cursor word'. It does this by (in this case) invoking a
- // command with some additional arguments identifying the command
- // being executed, the word being completed, and the previous word
- // (if any). Bash then expects a sequence of output lines to be
- // printed to stdout. If these lines all contain a common prefix
- // longer than the cursor word, bash will replace the cursor word
- // with that common prefix, and display nothing. If there isn't such
- // a common prefix, bash will display the lines in pages using 'more'.
- //
- // ** Strategy taken for command line completions:
- // If we can deduce either the exact flag intended, or a common flag
- // prefix, we'll output exactly that. Otherwise, if information
- // must be displayed to the user, we'll take the opportunity to add
- // some helpful information beyond just the flag name (specifically,
- // we'll include the default flag value and as much of the flag's
- // description as can fit on a single terminal line width, as specified
- // by the flag --tab_completion_columns). Furthermore, we'll try to
- // make bash order the output such that the most useful or relevent
- // flags are the most likely to be shown at the top.
- //
- // ** Additional features:
- // To assist in finding that one really useful flag, substring matching
- // was implemented. Before pressing a <TAB> to get completion for the
- // current word, you can append one or more '?' to the flag to do
- // substring matching. Here's the semantics:
- // --foo<TAB> Show me all flags with names prefixed by 'foo'
- // --foo?<TAB> Show me all flags with 'foo' somewhere in the name
- // --foo??<TAB> Same as prior case, but also search in module
- // definition path for 'foo'
- // --foo???<TAB> Same as prior case, but also search in flag
- // descriptions for 'foo'
- // Finally, we'll trim the output to a relatively small number of
- // flags to keep bash quiet about the verbosity of output. If one
- // really wanted to see all possible matches, appending a '+' to the
- // search word will force the exhaustive list of matches to be printed.
- //
- // ** How to have bash accept completions from a binary:
- // Bash requires that it be informed about each command that programmatic
- // completion should be enabled for. Example addition to a .bashrc
- // file would be (your path to gflags_completions.sh file may differ):
- /*
- $ complete -o bashdefault -o default -o nospace -C \
- '/usr/local/bin/gflags_completions.sh --tab_completion_columns $COLUMNS' \
- time env binary_name another_binary [...]
- */
- // This would allow the following to work:
- // $ /path/to/binary_name --vmodule<TAB>
- // Or:
- // $ ./bin/path/another_binary --gfs_u<TAB>
- // (etc)
- //
- // Sadly, it appears that bash gives no easy way to force this behavior for
- // all commands. That's where the "time" in the above example comes in.
- // If you haven't specifically added a command to the list of completion
- // supported commands, you can still get completions by prefixing the
- // entire command with "env".
- // $ env /some/brand/new/binary --vmod<TAB>
- // Assuming that "binary" is a newly compiled binary, this should still
- // produce the expected completion output.
- #ifndef GOOGLE_GFLAGS_COMPLETIONS_H_
- #define GOOGLE_GFLAGS_COMPLETIONS_H_
- namespace google {
- void HandleCommandLineCompletions(void);
- }
- #endif // GOOGLE_GFLAGS_COMPLETIONS_H_