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