Add deploySteps and variables to cppdbg

[xisui-MSFT]

Add deploySteps and variables to cppdbg. Spec available upon request.

There will be follow up PRs, which implement deploy in multiroot scenarios, and process picker for gdb extended-remote, separately.

[WardenGnaw]

In this PR, could you provide an example launch.json with variables and deploy and give a quick explanation of what would happen with those configuration fields set (or a GIF of it if it is working end to end.)

[xisui-MSFT]

In this PR, could you provide an example launch.json with variables and deploy and give a quick explanation of what would happen with those configuration fields set (or a GIF of it if it is working end to end.)

Sample launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Debug Pi1",
            "type": "cppdbg",
            "request": "launch",
            "variables": {
                "user": "pi",
                "host": "${input:targetIP}",
                "port": "22100",
                "program": "${command:cmake.launchTargetPath}",
                "targetDir": "/home/pi",
                "targetFilePath": "${targetDir}/${command:cmake.launchTargetFilename}"
            },
            "cwd": "${workspaceFolder}",
            "program": "${program}",
            "stopAtEntry": true,
            "MIMode": "gdb",
            "miDebuggerPath": "/usr/bin/gdb-multiarch",
            "miDebuggerServerAddress": "${host}:${port}",
            "deploySteps": [
                {
                    "type": "scp",
                    "files": "${program}",
                    "host": {
                        "user": "${user}",
                        "hostName": "${host}"
                    },
                    "targetDir": "${targetDir}"
                },
                {
                    "type": "ssh",
                    "host": {
                        "user": "${user}",
                        "hostName": "${host}"
                    },
                    "command": "chmod +x ${targetFilePath}",
                },
                {
                    "type": "ssh",
                    "host": {
                        "user": "${user}",
                        "hostName": "${host}"
                    },
                    "command": "gdbserver :${port} ${targetFilePath}",
                    "continueOn": "Listening on port",
                    "debug": true
                },
                {
                    "type": "ssh",
                    "host": {
                        "user": "${user}",
                        "hostName": "${host}"
                    },
                    "command": "${targetFilePath}",
                    "debug": false
                }
            ],
            "setupCommands": [
                {
                    "description": "Enable pretty-printing for gdb",
                    "text": "-enable-pretty-printing",
                    "ignoreFailures": true
                }
            ]
        }
    ],
    "inputs": [
        {
            "type": "promptString",
            "id": "targetIP",
            "description": "Enter the IP address of the target device"
        }
    ]
}

Stepps:

1. Expand all variables in this launch config that are not resolved by VS Code.
2. Run deploy steps. ask for password for scp/ssh steps. The authentication method is the same as using ssh in the terminal. For example, if key based authentication is used, then no authentication will be asked.

• Copy binary to the device using SCP.
• chom +x in case there are any permission issue.
• Start gdbserver when starting debugging; start the program only when starting without debugging.

3. Start debugging.

GIF:

[WardenGnaw]