Introduce SetFunction for profiles

.chloggen/function-equal.yaml

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+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: pdata/pprofile
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Introduce `Equal` method on the `Function` type
+
+# One or more tracking issues or pull requests related to the change
+issues: [13222]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

.chloggen/set-function.yaml

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+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: pdata/pprofile
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add new helper method `SetFunction` to set a new function on a line.
+
+# One or more tracking issues or pull requests related to the change
+issues: [13222]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]

pdata/pprofile/function.go

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+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package pprofile // import "go.opentelemetry.io/collector/pdata/pprofile"
+
+// Equal checks equality with another Function
+func (fn Function) Equal(val Function) bool {
+	return fn.NameStrindex() == val.NameStrindex() &&
+		fn.SystemNameStrindex() == val.SystemNameStrindex() &&
+		fn.FilenameStrindex() == val.FilenameStrindex() &&
+		fn.StartLine() == val.StartLine()
+}

pdata/pprofile/function_test.go

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+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package pprofile
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestFunctionEqual(t *testing.T) {
+	for _, tt := range []struct {
+		name string
+		orig Function
+		dest Function
+		want bool
+	}{
+		{
+			name: "empty functions",
+			orig: NewFunction(),
+			dest: NewFunction(),
+			want: true,
+		},
+		{
+			name: "non-empty identical functions",
+			orig: buildFunction(1, 2, 3, 4),
+			dest: buildFunction(1, 2, 3, 4),
+			want: true,
+		},
+		{
+			name: "with different name",
+			orig: buildFunction(1, 2, 3, 4),
+			dest: buildFunction(2, 2, 3, 4),
+			want: false,
+		},
+		{
+			name: "with different system name",
+			orig: buildFunction(1, 2, 3, 4),
+			dest: buildFunction(1, 3, 3, 4),
+			want: false,
+		},
+		{
+			name: "with different file name",
+			orig: buildFunction(1, 2, 3, 4),
+			dest: buildFunction(1, 2, 4, 4),
+			want: false,
+		},
+		{
+			name: "with different start line",
+			orig: buildFunction(1, 2, 3, 4),
+			dest: buildFunction(1, 2, 3, 5),
+			want: false,
+		},
+	} {
+		t.Run(tt.name, func(t *testing.T) {
+			if tt.want {
+				assert.True(t, tt.orig.Equal(tt.dest))
+			} else {
+				assert.False(t, tt.orig.Equal(tt.dest))
+			}
+		})
+	}
+}
+
+func buildFunction(name, sName, fileName int32, startLine int64) Function {
+	f := NewFunction()
+	f.SetNameStrindex(name)
+	f.SetSystemNameStrindex(sName)
+	f.SetFilenameStrindex(fileName)
+	f.SetStartLine(startLine)
+	return f
+}

pdata/pprofile/functions.go

@@ -0,0 +1,47 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package pprofile // import "go.opentelemetry.io/collector/pdata/pprofile"
+
+import (
+	"errors"
+	"fmt"
+	"math"
+)
+
+var errTooManyFunctionTableEntries = errors.New("too many entries in FunctionTable")
+
+// SetFunction updates a FunctionTable and a Line's FunctionIndex to
+// add or update a function.
+func SetFunction(table FunctionSlice, record Line, fn Function) error {
+	idx := int(record.FunctionIndex())
+	if idx > 0 {
+		if idx >= table.Len() {
+			return fmt.Errorf("index value %d out of range for FunctionIndex", idx)
+		}
+		mapAt := table.At(idx)
+		if mapAt.Equal(fn) {
+			// Function already exists, nothing to do.
+			return nil
+		}
+	}
+
+	for j, m := range table.All() {
+		if m.Equal(fn) {
+			if j > math.MaxInt32 {
+				return errTooManyFunctionTableEntries
+			}
+			// Add the index of the existing function to the indices.
+			record.SetFunctionIndex(int32(j)) //nolint:gosec // G115 overflow checked
+			return nil
+		}
+	}
+
+	if table.Len() >= math.MaxInt32 {
+		return errTooManyFunctionTableEntries
+	}
+
+	fn.CopyTo(table.AppendEmpty())
+	record.SetFunctionIndex(int32(table.Len() - 1)) //nolint:gosec // G115 overflow checked
+	return nil
+}

pdata/pprofile/functions_test.go

@@ -0,0 +1,123 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package pprofile
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSetFunction(t *testing.T) {
+	table := NewFunctionSlice()
+	f := NewFunction()
+	f.SetNameStrindex(1)
+	f2 := NewFunction()
+	f2.SetNameStrindex(2)
+	li := NewLine()
+
+	// Put a first function
+	require.NoError(t, SetFunction(table, li, f))
+	assert.Equal(t, 1, table.Len())
+	assert.Equal(t, int32(0), li.FunctionIndex())
+
+	// Put the same function
+	// This should be a no-op.
+	require.NoError(t, SetFunction(table, li, f))
+	assert.Equal(t, 1, table.Len())
+	assert.Equal(t, int32(0), li.FunctionIndex())
+
+	// Set a new function
+	// This sets the index and adds to the table.
+	require.NoError(t, SetFunction(table, li, f2))
+	assert.Equal(t, 2, table.Len())
+	assert.Equal(t, int32(table.Len()-1), li.FunctionIndex()) //nolint:gosec // G115
+
+	// Set an existing function
+	require.NoError(t, SetFunction(table, li, f))
+	assert.Equal(t, 2, table.Len())
+	assert.Equal(t, int32(0), li.FunctionIndex())
+	// Set another existing function
+	require.NoError(t, SetFunction(table, li, f2))
+	assert.Equal(t, 2, table.Len())
+	assert.Equal(t, int32(table.Len()-1), li.FunctionIndex()) //nolint:gosec // G115
+}
+
+func TestSetFunctionCurrentTooHigh(t *testing.T) {
+	table := NewFunctionSlice()
+	li := NewLine()
+	li.SetFunctionIndex(42)
+
+	err := SetFunction(table, li, NewFunction())
+	require.Error(t, err)
+	assert.Equal(t, 0, table.Len())
+	assert.Equal(t, int32(42), li.FunctionIndex())
+}
+
+func BenchmarkSetFunction(b *testing.B) {
+	for _, bb := range []struct {
+		name string
+		fn   Function
+
+		runBefore func(*testing.B, FunctionSlice, Line)
+	}{
+		{
+			name: "with a new function",
+			fn:   NewFunction(),
+		},
+		{
+			name: "with an existing function",
+			fn: func() Function {
+				f := NewFunction()
+				f.SetNameStrindex(1)
+				return f
+			}(),
+
+			runBefore: func(_ *testing.B, table FunctionSlice, _ Line) {
+				f := table.AppendEmpty()
+				f.SetNameStrindex(1)
+			},
+		},
+		{
+			name: "with a duplicate function",
+			fn:   NewFunction(),
+
+			runBefore: func(_ *testing.B, table FunctionSlice, obj Line) {
+				require.NoError(b, SetFunction(table, obj, NewFunction()))
+			},
+		},
+		{
+			name: "with a hundred functions to loop through",
+			fn: func() Function {
+				f := NewFunction()
+				f.SetNameStrindex(1)
+				return f
+			}(),
+
+			runBefore: func(_ *testing.B, table FunctionSlice, _ Line) {
+				for i := range 100 {
+					f := table.AppendEmpty()
+					f.SetNameStrindex(int32(i)) //nolint:gosec // overflow checked
+				}
+			},
+		},
+	} {
+		b.Run(bb.name, func(b *testing.B) {
+			table := NewFunctionSlice()
+			obj := NewLine()
+
+			if bb.runBefore != nil {
+				bb.runBefore(b, table, obj)
+			}
+
+			b.ResetTimer()
+			b.ReportAllocs()
+
+			for range b.N {
+				_ = SetFunction(table, obj, bb.fn)
+			}
+		})
+	}
+}