Introduce client/server separation

Refactor to introduce client/server separation, including a typed
client API and a HTTP REST server implementation.

Refactor the terminal to be an API consumer.

service/api/types.go

@@ -0,0 +1,99 @@
+package api
+
+// DebuggerState represents the current context of the debugger.
+type DebuggerState struct {
+	// BreakPoint is the current breakpoint at which the debugged process is
+	// suspended, and may be empty if the process is not suspended.
+	BreakPoint *BreakPoint `json:"breakPoint,omitempty"`
+	// CurrentThread is the currently selected debugger thread.
+	CurrentThread *Thread `json:"currentThread,omitempty"`
+	// Exited indicates whether the debugged process has exited.
+	Exited bool `json:"exited"`
+}
+
+// BreakPoint addresses a location at which process execution may be
+// suspended.
+type BreakPoint struct {
+	// ID is a unique identifier for the breakpoint.
+	ID int `json:"id"`
+	// Addr is the address of the breakpoint.
+	Addr uint64 `json:"addr"`
+	// File is the source file for the breakpoint.
+	File string `json:"file"`
+	// Line is a line in File for the breakpoint.
+	Line int `json:"line"`
+	// FunctionName is the name of the function at the current breakpoint, and
+	// may not always be available.
+	FunctionName string `json:"functionName,omitempty"`
+}
+
+// Thread is a thread within the debugged process.
+type Thread struct {
+	// ID is a unique identifier for the thread.
+	ID int `json:"id"`
+	// PC is the current program counter for the thread.
+	PC uint64 `json:"pc"`
+	// File is the file for the program counter.
+	File string `json:"file"`
+	// Line is the line number for the program counter.
+	Line int `json:"line"`
+	// Function is function information at the program counter. May be nil.
+	Function *Function `json:"function,omitempty"`
+}
+
+// Function represents thread-scoped function information.
+type Function struct {
+	// Name is the function name.
+	Name   string `json:"name"`
+	Value  uint64 `json:"value"`
+	Type   byte   `json:"type"`
+	GoType uint64 `json:"goType"`
+	// Args are the function arguments in a thread context.
+	Args []Variable `json:"args"`
+	// Locals are the thread local variables.
+	Locals []Variable `json:"locals"`
+}
+
+// Variable describes a variable.
+type Variable struct {
+	Name  string `json:"name"`
+	Value string `json:"value"`
+	Type  string `json:"type"`
+}
+
+// Goroutine represents the information relevant to Delve from the runtime's
+// internal G structure.
+type Goroutine struct {
+	// ID is a unique identifier for the goroutine.
+	ID int `json:"id"`
+	// PC is the current program counter for the goroutine.
+	PC uint64 `json:"pc"`
+	// File is the file for the program counter.
+	File string `json:"file"`
+	// Line is the line number for the program counter.
+	Line int `json:"line"`
+	// Function is function information at the program counter. May be nil.
+	Function *Function `json:"function,omitempty"`
+}
+
+// DebuggerCommand is a command which changes the debugger's execution state.
+type DebuggerCommand struct {
+	// Name is the command to run.
+	Name string `json:"name"`
+	// ThreadID is used to specify which thread to use with the SwitchThread
+	// command.
+	ThreadID int `json:"threadID,omitempty"`
+}
+
+const (
+	// Continue resumes process execution.
+	Continue = "continue"
+	// Step continues for a single instruction, entering function calls.
+	Step = "step"
+	// Next continues to the next source line, not entering function calls.
+	Next = "next"
+	// SwitchThread switches the debugger's current thread context.
+	SwitchThread = "switchThread"
+	// Halt suspends the process.
+	Halt = "halt"
+)