config.go

     1  package driver
     2  
     3  import (
     4  	"fmt"
     5  	"net/url"
     6  	"reflect"
     7  	"strconv"
     8  	"strings"
     9  	"sync"
    10  )
    11  
    12  // config holds settings for a single named config.
    13  // The JSON tag name for a field is used both for JSON encoding and as
    14  // a named variable.
    15  type config struct {
    16  	// Filename for file-based output formats, stdout by default.
    17  	Output string `json:"-"`
    18  
    19  	// Display options.
    20  	CallTree            bool    `json:"call_tree,omitempty"`
    21  	RelativePercentages bool    `json:"relative_percentages,omitempty"`
    22  	Unit                string  `json:"unit,omitempty"`
    23  	CompactLabels       bool    `json:"compact_labels,omitempty"`
    24  	SourcePath          string  `json:"-"`
    25  	TrimPath            string  `json:"-"`
    26  	IntelSyntax         bool    `json:"intel_syntax,omitempty"`
    27  	Mean                bool    `json:"mean,omitempty"`
    28  	SampleIndex         string  `json:"-"`
    29  	DivideBy            float64 `json:"-"`
    30  	Normalize           bool    `json:"normalize,omitempty"`
    31  	Sort                string  `json:"sort,omitempty"`
    32  
    33  	// Label pseudo stack frame generation options
    34  	TagRoot string `json:"tagroot,omitempty"`
    35  	TagLeaf string `json:"tagleaf,omitempty"`
    36  
    37  	// Filtering options
    38  	DropNegative bool    `json:"drop_negative,omitempty"`
    39  	NodeCount    int     `json:"nodecount,omitempty"`
    40  	NodeFraction float64 `json:"nodefraction,omitempty"`
    41  	EdgeFraction float64 `json:"edgefraction,omitempty"`
    42  	Trim         bool    `json:"trim,omitempty"`
    43  	Focus        string  `json:"focus,omitempty"`
    44  	Ignore       string  `json:"ignore,omitempty"`
    45  	PruneFrom    string  `json:"prune_from,omitempty"`
    46  	Hide         string  `json:"hide,omitempty"`
    47  	Show         string  `json:"show,omitempty"`
    48  	ShowFrom     string  `json:"show_from,omitempty"`
    49  	TagFocus     string  `json:"tagfocus,omitempty"`
    50  	TagIgnore    string  `json:"tagignore,omitempty"`
    51  	TagShow      string  `json:"tagshow,omitempty"`
    52  	TagHide      string  `json:"taghide,omitempty"`
    53  	NoInlines    bool    `json:"noinlines,omitempty"`
    54  	ShowColumns  bool    `json:"showcolumns,omitempty"`
    55  
    56  	// Output granularity
    57  	Granularity string `json:"granularity,omitempty"`
    58  }
    59  
    60  // defaultConfig returns the default configuration values; it is unaffected by
    61  // flags and interactive assignments.
    62  func defaultConfig() config {
    63  	return config{
    64  		Unit:         "minimum",
    65  		NodeCount:    -1,
    66  		NodeFraction: 0.005,
    67  		EdgeFraction: 0.001,
    68  		Trim:         true,
    69  		DivideBy:     1.0,
    70  		Sort:         "flat",
    71  		Granularity:  "", // Default depends on the display format
    72  	}
    73  }
    74  
    75  // currentConfig holds the current configuration values; it is affected by
    76  // flags and interactive assignments.
    77  var currentCfg = defaultConfig()
    78  var currentMu sync.Mutex
    79  
    80  func currentConfig() config {
    81  	currentMu.Lock()
    82  	defer currentMu.Unlock()
    83  	return currentCfg
    84  }
    85  
    86  func setCurrentConfig(cfg config) {
    87  	currentMu.Lock()
    88  	defer currentMu.Unlock()
    89  	currentCfg = cfg
    90  }
    91  
    92  // configField contains metadata for a single configuration field.
    93  type configField struct {
    94  	name         string              // JSON field name/key in variables
    95  	urlparam     string              // URL parameter name
    96  	saved        bool                // Is field saved in settings?
    97  	field        reflect.StructField // Field in config
    98  	choices      []string            // Name Of variables in group
    99  	defaultValue string              // Default value for this field.
   100  }
   101  
   102  var (
   103  	configFields []configField // Precomputed metadata per config field
   104  
   105  	// configFieldMap holds an entry for every config field as well as an
   106  	// entry for every valid choice for a multi-choice field.
   107  	configFieldMap map[string]configField
   108  )
   109  
   110  func init() {
   111  	// Config names for fields that are not saved in settings and therefore
   112  	// do not have a JSON name.
   113  	notSaved := map[string]string{
   114  		// Not saved in settings, but present in URLs.
   115  		"SampleIndex": "sample_index",
   116  
   117  		// Following fields are also not placed in URLs.
   118  		"Output":     "output",
   119  		"SourcePath": "source_path",
   120  		"TrimPath":   "trim_path",
   121  		"DivideBy":   "divide_by",
   122  	}
   123  
   124  	// choices holds the list of allowed values for config fields that can
   125  	// take on one of a bounded set of values.
   126  	choices := map[string][]string{
   127  		"sort":        {"cum", "flat"},
   128  		"granularity": {"functions", "filefunctions", "files", "lines", "addresses"},
   129  	}
   130  
   131  	// urlparam holds the mapping from a config field name to the URL
   132  	// parameter used to hold that config field. If no entry is present for
   133  	// a name, the corresponding field is not saved in URLs.
   134  	urlparam := map[string]string{
   135  		"drop_negative":        "dropneg",
   136  		"call_tree":            "calltree",
   137  		"relative_percentages": "rel",
   138  		"unit":                 "unit",
   139  		"compact_labels":       "compact",
   140  		"intel_syntax":         "intel",
   141  		"nodecount":            "n",
   142  		"nodefraction":         "nf",
   143  		"edgefraction":         "ef",
   144  		"trim":                 "trim",
   145  		"focus":                "f",
   146  		"ignore":               "i",
   147  		"prune_from":           "prunefrom",
   148  		"hide":                 "h",
   149  		"show":                 "s",
   150  		"show_from":            "sf",
   151  		"tagfocus":             "tf",
   152  		"tagignore":            "ti",
   153  		"tagshow":              "ts",
   154  		"taghide":              "th",
   155  		"mean":                 "mean",
   156  		"sample_index":         "si",
   157  		"normalize":            "norm",
   158  		"sort":                 "sort",
   159  		"granularity":          "g",
   160  		"noinlines":            "noinlines",
   161  		"showcolumns":          "showcolumns",
   162  	}
   163  
   164  	def := defaultConfig()
   165  	configFieldMap = map[string]configField{}
   166  	t := reflect.TypeOf(config{})
   167  	for i, n := 0, t.NumField(); i < n; i++ {
   168  		field := t.Field(i)
   169  		js := strings.Split(field.Tag.Get("json"), ",")
   170  		if len(js) == 0 {
   171  			continue
   172  		}
   173  		// Get the configuration name for this field.
   174  		name := js[0]
   175  		if name == "-" {
   176  			name = notSaved[field.Name]
   177  			if name == "" {
   178  				// Not a configurable field.
   179  				continue
   180  			}
   181  		}
   182  		f := configField{
   183  			name:     name,
   184  			urlparam: urlparam[name],
   185  			saved:    (name == js[0]),
   186  			field:    field,
   187  			choices:  choices[name],
   188  		}
   189  		f.defaultValue = def.get(f)
   190  		configFields = append(configFields, f)
   191  		configFieldMap[f.name] = f
   192  		for _, choice := range f.choices {
   193  			configFieldMap[choice] = f
   194  		}
   195  	}
   196  }
   197  
   198  // fieldPtr returns a pointer to the field identified by f in *cfg.
   199  func (cfg *config) fieldPtr(f configField) interface{} {
   200  	// reflect.ValueOf: converts to reflect.Value
   201  	// Elem: dereferences cfg to make *cfg
   202  	// FieldByIndex: fetches the field
   203  	// Addr: takes address of field
   204  	// Interface: converts back from reflect.Value to a regular value
   205  	return reflect.ValueOf(cfg).Elem().FieldByIndex(f.field.Index).Addr().Interface()
   206  }
   207  
   208  // get returns the value of field f in cfg.
   209  func (cfg *config) get(f configField) string {
   210  	switch ptr := cfg.fieldPtr(f).(type) {
   211  	case *string:
   212  		return *ptr
   213  	case *int:
   214  		return fmt.Sprint(*ptr)
   215  	case *float64:
   216  		return fmt.Sprint(*ptr)
   217  	case *bool:
   218  		return fmt.Sprint(*ptr)
   219  	}
   220  	panic(fmt.Sprintf("unsupported config field type %v", f.field.Type))
   221  }
   222  
   223  // set sets the value of field f in cfg to value.
   224  func (cfg *config) set(f configField, value string) error {
   225  	switch ptr := cfg.fieldPtr(f).(type) {
   226  	case *string:
   227  		if len(f.choices) > 0 {
   228  			// Verify that value is one of the allowed choices.
   229  			for _, choice := range f.choices {
   230  				if choice == value {
   231  					*ptr = value
   232  					return nil
   233  				}
   234  			}
   235  			return fmt.Errorf("invalid %q value %q", f.name, value)
   236  		}
   237  		*ptr = value
   238  	case *int:
   239  		v, err := strconv.Atoi(value)
   240  		if err != nil {
   241  			return err
   242  		}
   243  		*ptr = v
   244  	case *float64:
   245  		v, err := strconv.ParseFloat(value, 64)
   246  		if err != nil {
   247  			return err
   248  		}
   249  		*ptr = v
   250  	case *bool:
   251  		v, err := stringToBool(value)
   252  		if err != nil {
   253  			return err
   254  		}
   255  		*ptr = v
   256  	default:
   257  		panic(fmt.Sprintf("unsupported config field type %v", f.field.Type))
   258  	}
   259  	return nil
   260  }
   261  
   262  // isConfigurable returns true if name is either the name of a config field, or
   263  // a valid value for a multi-choice config field.
   264  func isConfigurable(name string) bool {
   265  	_, ok := configFieldMap[name]
   266  	return ok
   267  }
   268  
   269  // isBoolConfig returns true if name is either name of a boolean config field,
   270  // or a valid value for a multi-choice config field.
   271  func isBoolConfig(name string) bool {
   272  	f, ok := configFieldMap[name]
   273  	if !ok {
   274  		return false
   275  	}
   276  	if name != f.name {
   277  		return true // name must be one possible value for the field
   278  	}
   279  	var cfg config
   280  	_, ok = cfg.fieldPtr(f).(*bool)
   281  	return ok
   282  }
   283  
   284  // completeConfig returns the list of configurable names starting with prefix.
   285  func completeConfig(prefix string) []string {
   286  	var result []string
   287  	for v := range configFieldMap {
   288  		if strings.HasPrefix(v, prefix) {
   289  			result = append(result, v)
   290  		}
   291  	}
   292  	return result
   293  }
   294  
   295  // configure stores the name=value mapping into the current config, correctly
   296  // handling the case when name identifies a particular choice in a field.
   297  func configure(name, value string) error {
   298  	currentMu.Lock()
   299  	defer currentMu.Unlock()
   300  	f, ok := configFieldMap[name]
   301  	if !ok {
   302  		return fmt.Errorf("unknown config field %q", name)
   303  	}
   304  	if f.name == name {
   305  		return currentCfg.set(f, value)
   306  	}
   307  	// name must be one of the choices. If value is true, set field-value
   308  	// to name.
   309  	if v, err := strconv.ParseBool(value); v && err == nil {
   310  		return currentCfg.set(f, name)
   311  	}
   312  	return fmt.Errorf("unknown config field %q", name)
   313  }
   314  
   315  // resetTransient sets all transient fields in *cfg to their currently
   316  // configured values.
   317  func (cfg *config) resetTransient() {
   318  	current := currentConfig()
   319  	cfg.Output = current.Output
   320  	cfg.SourcePath = current.SourcePath
   321  	cfg.TrimPath = current.TrimPath
   322  	cfg.DivideBy = current.DivideBy
   323  	cfg.SampleIndex = current.SampleIndex
   324  }
   325  
   326  // applyURL updates *cfg based on params.
   327  func (cfg *config) applyURL(params url.Values) error {
   328  	for _, f := range configFields {
   329  		var value string
   330  		if f.urlparam != "" {
   331  			value = params.Get(f.urlparam)
   332  		}
   333  		if value == "" {
   334  			continue
   335  		}
   336  		if err := cfg.set(f, value); err != nil {
   337  			return fmt.Errorf("error setting config field %s: %v", f.name, err)
   338  		}
   339  	}
   340  	return nil
   341  }
   342  
   343  // makeURL returns a URL based on initialURL that contains the config contents
   344  // as parameters.  The second result is true iff a parameter value was changed.
   345  func (cfg *config) makeURL(initialURL url.URL) (url.URL, bool) {
   346  	q := initialURL.Query()
   347  	changed := false
   348  	for _, f := range configFields {
   349  		if f.urlparam == "" || !f.saved {
   350  			continue
   351  		}
   352  		v := cfg.get(f)
   353  		if v == f.defaultValue {
   354  			v = "" // URL for of default value is the empty string.
   355  		} else if f.field.Type.Kind() == reflect.Bool {
   356  			// Shorten bool values to "f" or "t"
   357  			v = v[:1]
   358  		}
   359  		if q.Get(f.urlparam) == v {
   360  			continue
   361  		}
   362  		changed = true
   363  		if v == "" {
   364  			q.Del(f.urlparam)
   365  		} else {
   366  			q.Set(f.urlparam, v)
   367  		}
   368  	}
   369  	if changed {
   370  		initialURL.RawQuery = q.Encode()
   371  	}
   372  	return initialURL, changed
   373  }
   374
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